LIBRARY OF CONGRESS. 

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UNITED STATES OF AMERICA. 



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HORSES' TEETH: 



A TBEATISB OX THEIB 



Mode of Development. 



PHYSIOLOGICAL RELATIONS, ANATOMY, MICIIOSCOPICAL CHAR- 
ACTER, PATHOLOGY, AND DENTISTRY; 



BASES ON THE WORKS OF WELL-KNOWN 



Odontologists and Veterinary Surgeons; 



TO WHICH IS ADDED A 



U 

a^^ 



TOCABULARY OF THE MEDICAL AND TECHNICAL WORDS USED. 




WILLI 




NEW YORK: 
PUBLISHED BY THE AUTHOR. 

1880. 



Copyright, 1879, by William H. Clakke. 



Smith & McDougai,, Electrotypers, 
82 Btfekmaii St., N. Y. 



PREFACE. 



LIKE all Special Works, the present volume will 
i encounter more or less public prejudice. How- 
ever, the thoroughness with which Special Works and 
Articles are usually prepared has somewhat changed 
public sentiment, and the tendency of the times ap- 
pears to be in their favor. General Works have their 
advantages, but thoroughness of detail is not usually 
among them. It may also encounter prejudice on 
account of the doctrine of Evolution which pervades 
its pages; but this should not be, for it refers almost 
exclusively to the Horse, and, besides, indicates Pro- 
gress. Nature's laws are immutable, and to oppose 
them is as foolish as to beat the head against a stone 
wall. Whatever may be said of the original thoughts 
in the book, the compiled matter is from the works of 
well-known authors, some of which are also Special 
Works. Further, many of the definitions in the Vo- 
cabulary are from Special Cyclopedic Articles. 

The w^ork is the result of less than twelve months 
of research and study, which is some excuse for the 
small proportion of original matter. While it is not 
exhaustive, it is believed that a good foundation has 
been laid whereon to build, and that it will meet the 
present requirements of the Veterinary Profession, and 
may also be useful to both Horsemen and Farmers. 



ly PKEFACE. 

In order to make the work acceptable to all classes 
of readers, much of the selected matter has been edited 
and more or less condensed, a vocabulary of most of 
the technical words used and parenthetical explana- 
tions have been made, and an attempt has been made 
to relieve the monotony of dry anatomy by inserting 
reference notes and headings that are at least apropos. 

As I neither understand Veterinary nor Human Sur- 
gery, an explanation, if not an apology, is required, for 
as a rule the trained surgeon only should exercise the 
prerogative of an Instructor. 

At the request of Stephen J. Cox, Esq., I consented 
to become the Editor of a book whereof Mr. Charles D. 
House was to have been author. Mr. House furnished 
the facts for which he has received credit, and then 
abandoned the project. Whether I acted wisely or not 
in completing the work myself, and whether Mr. Cox 
does or does not deserve thanks for inducing me to 
begin it, is for the reader to decide. 

I am indebted to the Astor Library for the use of 
many books ; also to the Cooper Union ; to Prof. J. M. 
Heard, of the New York College of Veterinary Sur- 
geons, for the use of books and for valuable sugges- 
tions; also to Prof. F. G. Fairfield of the same College 
for the interest he took in the parts relating to micros- 
copy, and to Surgeons J. S. and C. C. Cattanach for 
the use of books and anatomical specimens. To Prof. 
John W. Draper, of the University of the City of New 
York, wlio perceived at a glance that the subject is 
"so sugg-estive;" Dr. George Thurber, of the Orange 
Judd Company, and W. B. Smith, Esq., of the Authors' 
Publishing Co., I am under obligation for encourage- 
ment to persevere in my labors. 

W. H. C. 



CONTENTS. 



PAGE 

INTRODUCTION '^ 

CHAPTER I. 

TOOTH-GERMS (ODONTOGENY). 

Periods at wliicli the Germs are visible in the Fetus.— Den- , 
tine and Enamel Germs.— A Cement Germ in the Foal. | 
—The Horse's Upper Grinders said to be developed 
from Five Germs, th3 Lower from Four. -Similar de- 
velopment of the Human Teeth 31 

CHAPTER II. 

THE TEMPORARY DENTITION. 
Twelve Incisors and Twelve Molars.— Why the Incisors 
are called " Nippers."— The Treatment of Foals Affects 
Teething.— Temporary Teeth Absorbed by Permanent. 47 

CHAPTER III. 

THE PERMANENT DENTITION. 
Distinction between Premolars and Molars.--The Bow-like 
Incisors.— Contrasts between Upper and Lower Grmd- 
ers and Rows formed bv them.— The Incisors saved 
from Friction.— Hors3s' teeth compared with those of 
other Animals.— Measaremeuts.— Time's Changes, &c. 53 

CHAPTER IV. 

THE CANINE TEETH OR TUSHES. 
Practically Useless.— Diff 3 rent in their Nature from other 
Teeth — Wers they formerly Weapons of Offense and 
Defense?— Views of Profs. Darwin, Hanter, Bell, You- 
att, and Winter.— Time of Cutting a Critical Period. . 75 

CHAPTER Y. 

THE REMNANT TEETH. • 

Usually rea:arded as Phenomenons.— The Name.— Traced 
to Fossil Hors-s. in which (in the Pliocene Period) they 
Ceased to be Fnnt^tionally Developed.— Nature's Meta- 
morphoses.—" The Agencies which are at work in Mod- 
eling- Animal and Veqretable Forms."- Why they are 
often, as it were, Prematurely Lost.— Fossil Horses. . . 94 



Vi COjnTENTS. 

PAGE 

CHAPTER VI. 

DENTAL- CYSTS AND SUPERNUMERAKY TEETH. 

Teeth jrrowing in various parts of the Body. — Some very- 
Prolific Cysts, Froduciiig a Second, it not a Third, 
•'Dentition." — Rexjorts and Theories oi Scientific Men. 115 

CHAPTER VIL 

HORSES' TEETH UNDER THE MICROSCOPE. 

The Dentinal Tubes, Enamel Fibers, and Cemental Canals 

Descriijed and Contrasted 130 

CHAPTER Vni. 

THE PATHOLOGY OF THE TEETH. , 

Importance of the Subject. — ^Caries caused by Inflamed 1 

Pulps, Blov/s, Virus, and Morbid Diathesis. — Supernu- 
merary Teeth and other Derangements. — Trephining 
the Sinuses. — Gutta-Percha as a Filling. — Cleaning the 
Teeth.— A Diseased Fossil Tooth 136 

CHAPTER IX. 

THE DENTISTRY OF THE TEETH. 

Eeports of Oases Treated by Various Surgeons. — Gutta- 
percha as a Filling for Trephined Sinuses. — Teeth 
Pressing against the Palate. — Death of a Horse from 
Swallo^ving a Diseased Tooth 175 

CHAPTER X. 

FRACTURED JAWS. 

How Caused, and how to Distinguish an Abrasion of the 
Gums from a Fracture of the Bone. — Replacing an Eye, 
Amputating part of a Lower Jaw, taking a Fractur£d 
Tooth and Bones out through the Nostril, &c 194 

CHAPTER XI. 

THE TEETH AS INDICATORS OF AGE. 

Their various ways of Indicating Age.— The "Mark's" 
Twofold Use.— The Dentinal Star.— Marks with too 
much Cement. — Tricks of the Trade.— Crib-biting. — 
\ Signs of Age Independent of the Teeth. T. . . 203 

CHAPTER XIL 

THE TRIGEMINUS OR FIFTH PAIR OF NERVES. 

Its Nature and thn Relation it bears to the Teeth. — Its 

Course in the Horse and in Man 216 

VOCABULARY 227 

INDEX 257 



INTRODUOTIOF. 



The following matter, which is designed to give at 
least a s3aiopsis of the fundamental principles of dental 
science, is compiled from the works of the best known 
odontologists. It is somewhat heterogeneous in its 
make-up, and is, moreover, considering that it is an 
Introduction to a -special work, anomalous, being 
rather an adjunct to than an explanation of the work 
itself. Its lack of coherency and the few repetitions, 
the inevitable concomitants of all compilations, are 
offset by the interest of its historical records and the 
scope and clearness of its thoughts and deductions. 
While it does not treat specially of horses' teeth, it is 
just as applicable to them as to human teeth, or to 
those of any of the other animals mentioned. It is 
believed that the student of dental science will find 
the matter as useful as it is interesting. 

In his work entitled "The Anatomy of Vertebrates" 
(vol. i, pp. 357-8), Prof. Richard Owen says : 

"A tooth is a hard body attached to the mouth or 
beginning of the alimentary canal, partially exposed, 
when developed. Calcified teeth are peculiar to the 
vertebrates, and may be defined as bodies primarily, if 
not permanently, distinct from the skeleton, consisting 



Viii INTRODUCTION'. 

oi' a cellular and tubular basis of animal matter, con- 
taining earthy particles, a fluid, and a vascular pulp. 

**In general, the earth is present in such quantity 
as to render the tooth harder than bone, in which case 
the animal basis is gelatinous, as in other hard parts 
where a great proportion of earth is combined with 
animal matter. In a very few . instances, among the 
vertebrate animals, the hardening material exists in a 
much smaller proportion, and the animal basis is albu- 
minous ; the teeth here agree, in both chemical and 
physical qualities, with bone. 

'^I propose to call the substance which forms the 
main part of all teeth dentine.* The second tissue, 
which is the most exterior in situation, is the cement. 
The third tissue, which, when present, is situated be- 
tween the dentine and cement, is the enamel. 

" Dentine consists of an organized animal basis and 
of earthy particles. The basis is disposed in the form 

* In a reference note in the Introduction to liis " Odontogra- 
phy," Prof. Owen says: "Besides the advantage of a substan- 
tive for an unquestionably distinct tissue under all its modifica- 
tions in the animal kingdom, the term dentine may be inflected 
adjectively, and the properties of this tissue described without 
the necessity of periphrasis. Thus we may speak of the ' denti- 
nal' pulp, 'dentinal' tubes or cells, as distinct from the corre- 
sponding properties of the other constitueiits of a tooth. The 
term 'dental' will retain its ordinary sense, as relating to the 
entire tooth or system of teeth." 

Wote.— The particular paragraph to which the above note re- 
fers is from Prof. Owen's " Odontography." " The Anatomy of 
Vertebrates," having been written about twenty-five years sub- 
sequent to the " Odontography," and therefore reflecting the 
Professor's riper thoughts, the extracts made from it were sub- 
stituted for very similar matter in the " Odontography." 



II^TRODUCTIOK. IX 

of compartments or cells, and extremely minute tubes. 
The earthy particles have a twofold arrangement, be- 
ing either blended with the animal matter of the in- 
terspaces and parietes of the tubes, or contained in a 
minute granular state in their cavities. The density 
of the dentine arises principally from the proportion 
of earth in the first of these states of combination. 
The tubes contain, near the formative pulp, filament- 
ary processes of that part, and convey a colorless fluid, 
probably transuded 'plasma.' They thus relate not 
only to the mechanical conditions of the tooth, but to 
the vitality and nutrition of the dentine. This tissue 
has few or no canals large enough to admit capillary 
vessels with the red particles of blood, and it has been 
therefore called * unvascular dentine.' 

" Cement always closely corresponds in texture with 
the osseous tissue of the same animal ; and whenever 
it occurs of different thickness, as upon the teeth of 
the horse, sloth, or ruminant, it is also traversed, like 
bone, by vascular canals. When the osseous tissue is 
excavated, as in dentigerous vertebrates above fishes, 
by minute radiated cells, forming, with their contents, 
the ' corpuscles of Purkinje,' these are likewise present, 
of similar size and form, in the cement, and are its 
chief characteristic as a constituent of the tooth. The 
hardening material of the cement is partly segregated 
and combined with the parietes of the radiated cells 
and canals, and is partly contained in disgregated 
granules in the cells, which are thus rendered white 
and opaque, viewed by reflected light. The relative 
density of the dentine and cement varies according to 
the proportion of the earthy material, and chiefly of 
that part which is combined with the animal matter 
in the walls of the cavities, as compared with the size 



X IKTHODUCTIOK. 

and number of the cavities themselves. In the complex 
grinders of the elei^hant, the masked boar, and the 
copybara, the cement, which forms nearly half the 
mass of the tooth, wears dov>m sooner than the dentine. 
" The enamel is the hardest constitnent of a tooth, 
and, consequently, the hardest of animal tissues; but 
it consists, Uke the other dental substances, of earthy 
matter arrans^ed by organic forces in an animal matrix. 
Here, however, the earth is mainly contained in the 
canals of the animal membrane, and, in mammals and 
reptiles, completely fills those canals, which are com- 
paratively wide, whilst their parietes are of extreme 
tenuity. The hardening salts of the enamel are not 
only present in far greater proportion than in the den- 
tine and cement, but, in some animals, are peculiarly 
distinguished by the presence of the fluate of lime." 

Again Prof. Owen says ("Anat. of Vert." vol. i, pp. 
359-60) : 

*"' Teeth vary in num'ber, size, form, structure, modi- 
fications of tissue, position, and mode of attachment 
in different animals. They are principally adapted for 
seizing, tearing, dividing, pounding, or grinding the 
food. In some animals they are modified to serve as 
weapons of offense and defense; in others, as aids in 
locomotion, means of anchorage, instruments for up- 
rooting or cutting down trees, or for transport and 
working of building materials. They are characteristic 
of age and sex, and in man they have secondary rela- 
tions subservient to beauty and to speech, 

"Teeth are always most intimately related to the 
food and habits of the animal, and are therefore highly 



INTRODUCTIOiT. Xl 

interesting to the ph3^siologist. They form for the 
same reason most important guides for tlie naturalist 
.in the classilication of animals; and their A'alue, as 
zoological characters, is enhanced by the facihty with 
which, from their position, they can be examined in 
living or recent animals. The durability of their tis- 
sues renders them not less available to the paleontolo- 
gist in the determination of the nature and affinities 
of extinct species, of whose organization they are often 
the sole remains discoverable in the deposits of former 
periods of the earth's history." 

Prof. A. Chauveau says (" Comparative Anatomy of 
theT)omesticated xinimals") : 

"Identical inxill our domesticated animals by their 
general disposition, mode of development, and struc- 
ture, in their external conformation the teetli present 
notable diffarences, the study of which offers the 
greatest interest to the naturalist. For it is on the 
form of its teeth that an animal depends for its mode 
of alimentation; it is the regime, in its turn, which 
dominates the instincts, and commands the diverse 
modifications in the apparatus of the economy; and 
there results from this law of harmony so striking a 
correlation between the arrangement of the teeth and 
the conformation of the other organs, that an anato- 
mist may truly say, 'Give me the tooth of an animal, 
and I will tell you its habits and structure.'" 

In a letter which I wrote to Prof. Theodore Gill, of 
the Smithsonian Institution, Washington, D. C, I 
asked what there was about teeth that enabled natu- 
ralists to tell so much by them. In reply he said : 



Xii INTRODUCTION'. 

*' The teeth are quite constant in the same type, are 
generally appreciably modified according to family, are 
the most readily preserved in a fossil state, and are in 
direct relation with the economy of the animal. Hence 
they furnish the best indications of the relations of 
the animal to which they belonged, especially in cases 
where the type was not very different from an existing 
one. In the case of the older and more aberrant types, 
liowever, the indications furnished by the dentition 
should be accepted with great caution." 

In the Introduction to his " Odontography '^ Prof. 
Owen gives, besides his own and other men's views, a 
history "of the leading steps to the present knowl- 
edge" of dental science (that is, up to 1844), of which 
the following are extracts : 

" As regards the teeth, the principle of cbief import 
to the physiologist arises out of the fact, which has 
been established by microscopic investigations, that the 
earthy particles of dentine are not confusedly blended 
with the animal basis,' and the substance arranged in 
superimposed layers, but that these particles are built 
up with the animal basis as a cement, in the form of 
tubes or hollow columns, in the predetermined arrange- 
ment of which there may be discerned the same rela- 
tion to the acquisition of strength and power of resist- 
ance in the due direction, as in the disposition of the 
columns and beams of a work of human architecture. 

" Whoever attentively observes a polished section or 
a fractured surface of a human tooth may learn, even 
Vv^ith the naked eye, that the silky and iridescent luster 
reflected from it in certain directions is due to the 
presence of a fine fibrous structure. 



INTR0DUCTI05T. xiii 

" Malpighi,* in whose works may be detected the 
gei'ins of many important anatomical truths that have 
subsequently been matured and established, says the 
teeth consist of two parts, of which the internal bony 
layers (dentine) seem to be composed of fibrous and, as 
it were, tendinous capillaments reticularly interwoven. 

"LeeuwTnhoek,t having applied his microscopical 
observations to the structure of the teeth, discovered 
that the apparent fibers were really tubes, and he com- 
municated a brief but succinct account of his discovery 
to the Royal Society of London, which was published, 
together with a figure of tlie tubes, in No. 140 of their 
Transactions. This figure of the dentinal tubes, with 
additional observations, again appeared in the Latin 
edition of Leeuwenhoek's works, published at Leyden 
in 1730. The dentine of the human teeth, and also 
that of yonng hogs, is described as being * formed of 
tubuli spreading from the cavity in the center to the 
circumference.' He computed that he saw a hundred 
and twenty of the tubuli within tlie forty-fifth part of 
an inch. He was awara also of the peculiar substance 
now termed the cement, or crusta jwtrosa, which enters 
mto the composition of the teeth of the horse and the 
ox. 

"These discoveries may be said to have appeared 
before their time. The •contemporaries of Leeuwen- 

* An Italian physician ; born in 1628 ; died in 1604. He was 
the first to apply the newly -invented microscope in the study of 
anatomy. 

X A Dutch naturalist and manufacturer of optical instruments. 
His microscopes were said to be the best in Europe. Besides 
his dental discoveries, he discovered the red globules of the 
blood, the infusorial animalcules, and that of the spermatozoa. 
Born in Delft October 34, 1632 ; died there Au^st 26, 1723. 



Xiv IHTRODtJCTIOK. 

hoek were not prepared to appreciate them ; besides 
they could neither repeat nor confirm them, for his 
means of observation were pccuHarly his own; and 
hence it has happened that, with tlie exception of the 
learned Portal,* they have either escaped notice, or 
have been designedly rejected by all anatomists until 
the time of the confirmation of their exactness and 
truth by Purkinje in 1835." 

Continuing the subject. Prof. Owen further says of 
the three constituent parts of teeth — dentine, enamel, 
and cement — beginning with 

THE DENTIIy^E. 

'•'Purkinje states that the dentine consists, not of 
superimposed layers, but of fibers arranged in a homo- 
geneous intermediate tissue, parallel with one another, 
and perpendicular to the surface of the tooth, running 
in a somewhat wavy course from the internal to the 
external surface, and he believed these fibers to be 
really tubular, because on bringing ink into contact 
with them, it was drawn in as if by capillary attraction. 

" On the publication of this discovery, it was imme- 
diately put to the test by Prof. Miiller, by whom the 
tubular structure of the denthie was not only con- 
firmed, but the nature and one of the offices of the 
tubes were determined. He observed that the white 
color of a tooth was confined to these tubes, which were 
imbedded in a semitransparent substance, and he found 
that the whiteness and opacity of the tubes were re- 
moved by acids. On breaking a thin lamella of a tooth 
transversely with regard to its fibers, and examining 
the edge of the fracture, Miiller perceived tubes pro- 

* " Histoire de I'Anatomie ct de la Cliirurgie,-' Paris, 1770. 



INTRODUCTION". XV 

jecting here and there from the surfaces. They were 
white and opaque, stiff, straight, and apparently not 
flexible. Tliis appearance is well represented in the 
old figure by Leeuwenhock. If the lamellae had been 
previously acted upon by acid, the projecting tubes 
were flexible and transparent, and often very long. 
Hence Miiller inferred that the tubes have distinct 
walls, consisting of an animal tissue, and that, besides 
containing earthy matter in their interior, their tissue 
is, in the natural state, impregnated with calcareous 
salts."* 

THE CEMENT. 

« The organized structure and microscopic character 
of the cem!ent were first determined by Purkinje and 
Faenkel, and the acquisition of these facts led to the 
detection of the tissue in the simple teeth of man and 
carnivorous animals. The cemen fc is most conspicuous 
where it invests the fang of the tooth, and increases m 
thickness as it approaches the apex of the fang. The 
animal constituent of this part of the cement had been 
recognized by Berzelius as a distinct investment of the 
dentine long before the tissue of which it formed the 
basis was clearly recognized in simple teeth. Berzelius 
describes the cemen tal membrane as being less consist- 
ent than the animal basis of the dentine, but resistmg 

* If Lord Bacon's theory is correct, the probability is that these 
tubes contain something besides earthy matter and calcareous 
saltr,, to wit, spirit. In " Novum Organum " lie says (B. Mon- 
tagu, vol.xiv, p. 417): "All things abhor a solution ot their 
continuity, but vet in proportion to their rarity. The more rare 
the bodies be, the more they suffer themselves to be thrust into 
small and narrow passatjes; for water will go into a passage 
which dust will not ^o into, air whix^h water vAM not go into, 
and flams and spirit which air will not go into." 



Xvi IKTRODUCTIOK". 

longer the solvent action of boiling water, and retain- 
ing some fine particles of the earthy phosphates when 
all such earth liad been extracted from the dentinal 
tissue. Cuvier also states that the cement is dissolved 
with more difficulty in acid than the other dental tis- 
sues. Retzius,* however, states that the earth is 
sooner extracted by acid from the cement than from 
the dentine of the teeth of the horse. 

*''In recent mammalian cement the radiated cells, like 
the dentinal tubes, owe their whiteness and opacity to 
the earth which they contain. According to Eetzius, 
* numerous tubes radiate from the cells, which, being 
dilated at their point of beginning, give the cells the 
appearance of an irregular star. These tubes form 
numerous combinations with each other, partly direct 
and partly by means of fine branches of t¥o"oo"^^^ ^^ 
-g-g-i-oo-th of an inch in diameter. The cells vary in 
size. The average size of the Purkinjean cells in hu- 
man cement is jeVo^^^ c>f an inch. In sections made 
transversely to the axis of the tooth, it is clearly seen 
that tiiese cells are arranged in parallel or concentric 
striae, of which some are more clearly and others more 
faintly visible, as if the cement were deposited in fine 
and coherent layers.' The layer of cement is found in 

*Prof. Retzius, of tlie University of Stockholm, informs us 
that he had heen led by the iridescence of the fractured surface 
of the substanco of a tontli to conceive that that appearance was 
du3, as in the crystalline lens, to a fine fibrous structure, and that 
he communicated his opinions as to the ren^ular arranofement of 
these fibers to some of his colleagues in 1834, In 1835, having 
obtained a powerful microscope, he began a series of more exact 
researches on the intimate structure of the teeth in man and 
the lower animals, which he communicated to the Royal Acad- 
emy of Sciences at Stockholm on January 13, 1836, being then 
unacquainted with the discoveries of Purkinje. — Owen. 



INTRODUCTION". Xvii 

the deciduous teeth, but is relatively thinner, and the 
Purkinjeiin cells are more irregular. 

'-'In growing teeth, with fangs not fully formed, the 
cement is so thin that the Purkinjean cells are not 
visible. It looks like a fine membrane, and has been 
described as the periosteum of the fangs; but it in- 
creases in thickness with the age of the tooih, and is 
the seat and origin of what are called exostoses of the 
fang, which are wholly composed of it.' These growths 
are subject to the formation of abscesses, and all the 
morbid actions of true bone. 

"It is the presence of this osseous substance which 
renders intelligible many well-known experiments of 
which human teeth have been the subjects, such as 
their transplantation and adhesion into the combs of 
cocks, and the establishment of a vascular connection 
between the tooth and the comb. 

"Under every modification the cement is the most 
highly organized and most vascular of the dental tis- 
sues, aud its chief use is to form the bond of vital 
union between the denser and commonly unvascular 
constituents of the tooth and the bone in which the 
tooth is implanted. In a few reptiles (now extinct), 
and in the herbivorous mammalia, the cement not only 
invests the exterior of the teeth, but penetrates their 
substance in vertical folds, varying in number, form, 
extent, thickness, and degree of complexity, and con- 
tributing to maintain that inequality of the grinding 
surface of the tooth whicli is essential to its function 
as an instrument for the comminution of vegetable 
substances." * 

* Cement Mistaken fou Taetah (ODONTOT/iTnosV — Sur- 
geon E. Mayliew says ("The Horse's Mouth," &c.): "Within 
the alveolar cavity, the ci'usla petrosa, which becomes of cou* 



Xvm IKTRODUCTIOIT. 



THE EK"AMEL. 

"The higlier an animal is placed in the scale of or- 
ganization, tiie more distinct and characteristic are not 
only the various organs of the body, but the different 
tissues which enter into their composition. This law 
is well exemplified in the teeth, although in the com- 
parison of these organs we are necessarily limited to 
the range of a single primary group of animals. We 
have seen, for example, that the dentine is scarcely 
distinguisha])le from the tissue of the skeleton in the 
majority of fishes; but that its peculiarly dense, un- 
vascular, and resisting structure, which is the excep- 
tionable condition in fishes, is its prevalent character 
in the teeth of the higher vertebrates. 

"So likewise with the enamel. This substance, 
which under all its conditions bears a close analogy 
with the dentine, is hardly distinguishable from that 
tissue in the teeth of many fishes. The fine calciger- 
ous* tubes are present in both substances, and undergo 
similar subdivisions, the directions only of the trunks 

siderable thickness ftround the fang", is of a yellowish-white 
color ; but where, as on the crown of the tooth, it is exposed to 
the chemical action of food and air, it presents a darker aspect, 
and resembles an accmnulation of tartar, for which indeed it 
has been mistaken. It fills up the infimdibula of the grinders 
and lines those of the incisors. It is pierced by all the vessels 
wliich nourish the teeth." 
! The editor of ''The Veterinrtrian " (18i9), in a "review" of 
Mr, Mayhew's work, says: "Both English and French veteri- 
nary writers have mistaken the crusta petrosa for tartar, not be- 
ing aware of its existence inside as well as outside of the tooth." 

* This word is peculiar to if not originated by Prof. Owen. It 
is synonymous with the word Ccdciferous (limy). 



INTRODUCTION". XIX 

and branches being reversed, agreeably with the con- 
trary course of their respective developments. The 
proportion of animal matter is also greater in the 
enamel of the teeth of nshes than in the higher verte- 
brala, and the proportion of tlie calcareous salts incor- 
porated with the animal constituent of the walls of 
the tubes is greater as compared with the subcrystal- 
line part deposited in the tubular cavities. 

"The enamel may be distinguished, independently 
of its microscopic and structural characters, by its 
ghstening, subtransparent substance, which is white 
or bluish-white by reflected light, but of a gray-brown 
color when viewed, under the microscope, by trans- 
mitted light. * ^ * The enamel of the molar 
tooth of a calf, which has just begun to appear above 
the gum, and which can readily be detached from the 
dentine, especially near the beginning of the fangs, is 
resolvable into apparently fine prismatic fibers. If 
these fibers be separately treated with dilute muriatic 
acid, and the residue examined with a moderate mag- 
nifying power, in distilled water, or, better, in dilute 
alcOliol, portions of more or less perfect membranous 
sheaths or tubes will be discerned, which inclosed the 
earthy matter of the minute prism, and served as the 
mold in which it was deposited. 

"Prof. Ketzius, who obtained a small portion of 
organic or animal substance from the enamel-fibers of 
an incompletely-formed tooth of a horse, conjectured 
that it was a deposition of that fluid whicli originally 
surrounds the loose enamel-fibers, and that ^in pro- 
portion as these fibers are pressed tighter together, and 
additional fibers are wedged between them, the organic 
deposition is forced away.' 

*'Retzius accurately describes the enamel-fibers of 



XX INTRODUCTION". 

the horse as presenting the form of angular needles, 
about ^i^Vo^^^ <^f ^^^ ii^ch in diameter, which are trav- 
ersed by minute and close-set transverse striae over 
the whole or a part of the fiber; and he conjectures 
that if the enamel-fiber be a mass of the calcareous 
salts, surrounded by an organic capsule, that the stride 
may then belong to the capsule, and not to the enamel- 
fiber. The later researches of Dr. Schwann add to the 
probability of this conjecture; and the absence of the 
minute striae in the enamel of fossil mammalian teeth, 
at least in the examples which I have submitted to 
microscopic investigation, may depend upon the de- 
struction of the original organic constituent of the 
enamel. 

"The enamel-fibers are directed at nearly right 
ansfles to the surface of the dentine, and their central 
or inner extremities rest in slight but regular depres- 
sions on the periphery of the coronal dentine. Thus 
in the human tooth, the fibers which constitute the 
masticating surface are perpendicular, or nearly so, to 
that surface, while those at the lower part of the crown 
are transverse, and consequently have a position best 
adapted for resisting the pressure of the contiguous 
teeth, and for meeting the direction in which external 
forces are most likely to impinge upon the exposed 
crown of the tooth. The strength of the enamel-fibers 
is further increased by the graceful, wavy curves in 
which they are disposed. These curves are in some 
places parallel, in others opposed. Their concavities 
are commonly turned toward each other, where the 
shorter fibers, which do not reach the exterior of the 
enamel, abut by their gradually attenuated peripheral 
extremities upon the longer fibers. Other shorter fibers 
extend from the outer surface of the enamel toward 



II^TRODUCTION". XXI 

the dentine, and are wedged into the interspaces of 
the longer fibers. In the teeth of fishes, the calciger- 
ous tubes or fibers of the enamel, which ramify and 
subdivide like those of the dentine, have their trunks 
turned in the opposite direction, or toward the periph- 
ery of the tooth. So likewise in human teeth the 
analogous condition may be discerned in the slightly 
augmented diameter of the enamel-fibers at their pe- 
ripheral as compared with their central extremities. 
AVhen the extremities of the human enamel-fibers are 
examined with a magnifying power of 300 linear 
dimensions, by reflected light, they are seen to be co- 
adapted, like the cells of a honey-comb, and, like these, 
to be, for the most part, hexagonal. 

"The internal surface of the enamel is marked hy 
fine transverse fines or ridges, of which Retzius counted 
twenty-four in tlie vertical extent of one-tenth of an 
English inch of the crown of a human incisor. These 
lines are parallel and wavy, and, like the analogous 
markings on the surface of shells, indicate the succes- 
sive formation of the belts of enamel-fibers that encircle 
the crown of the tooth. They may be traced around 
the whole crown, but are very faint upon its inner or 
posterior surface. Retzius cites Leeuwenhoek as the 
discoverer of these superficial transverse lines of the 
enamel, but the older observer supposed them to be 
indicative of the intervals between the successive move- 
ments in the cutting of the tooth through the gum. 

" The enamel, by virtue of its physical qualities of 
density and durability, forms the chief mechanical 
defense of the tooth, and is consequently limited in 
most simple teeth to tlie exterior surface of the exposed 
portion of the dentine, forming the crown of the tooth. 
* * ''^ In the herbivorous mammalia, with the 



Xxii INTRODUCTION. 

exception of the Edentata, vertical folds or processes 
of the enamel are continued into the substance of the 
tooth, varying in numher, form, extent, and direction, 
and producing, by their superior density aud resistance, 
the ridged inequalities of the grinding surface on which 
its efficacy in the trituration of vegetable substances 
depends." 

Dr. Boon Hayes's thoughts are thus recorded in a 
"Medical Circular," extracts from which appear in 
"The Veterinarian" for 1853 (pp. 535-G) : 

" In the first place, observe the pulpal cavity, which 
is to the tooth what the medullary cavity is to bone. 
Both originate in the same way. Into it passes an 
artery, a vein, and a nerve. These ramify upon the 
pulpal surface, the artery carrying blood to the denti- 
nal tubuli, whence the liquor sanguinis (not blood 
corpuscles), proceeds to the nourishment of this ap- 
parently inorganic mass. 

"In the teeth of some animals this cavity seems to 
send off diverticula between tlie dentinal tubuli, as if 
for the purpose of supplying them with more vascu- 
larity. The dentinal tubes open on the walls of the 
pulpal cavity, and thence radiate to the enamel supe- 
riorly and the crusta petrosa interiorly. I think it 
would not be difficult to prove that caries of the teeth 
more frequently proceeds from inflammation begin- 
ning in this cavity than from any other cause. 

"When the tubes of the dentine are examined with a 
high magnifying power, and by transmitted light, they 
appear dark. They are much more minute in diameter 
than the blood globules; hence the liquor sanguinis 
alone cm penetrate them for their nourishment; so 



INTRODUCTION. XXUl 

that the teeth are in the same condition as bone in this 
respect. 

"The dentinal tubes, as before said, appear dark; 
the hghter and apparently broader masses are the real 
substance of the dentine. In this, and especially near 
the layer closest to the enamel, dentinal cells are some- 
times seen, which may probably be analogous to the 
lacunae of bone. 

"If the dentinal curvatures are examined, it will be 
seen that they are of two kinds. One set is in bold 
and evident curves; the other is not so e^^dent, but it 
exists, nevertheless, and a little patience and a high 
magnifying power will demonstrate the fact that its 
curves are upon the curves of the first set. The former 
are called the primary, the latter the secondary curves 
of the dentinal tubuli (in botanical description, a 
biserrated leaf). From the tubuli minute bracelets 
are given off on the sides, and toward the end the tubes 
terminate, either in cells, by anastomosis, or by looping 
back upon themselves. 

"The cement at first envelops the whole tooth, but 
soon wears off the crown and as far down as the neck. 
Compared with the dentine and enamel, it is very soft, 
and more closely resembles bone ; in fact in some ani- 
mals it is continuous with the bone of the jaw, thus 
proving its identity. It contains lacunae and canalic- 
uli, and, when there is a large mass of it, something 
like Haversian canals. 

" There is a a^reat analoory between tooth and bone. 
In the cement there is absolute likeness, and in the 
dentine analogies too striking to be overlooked, viz., 
the tubuli, analogous to tlie canaliculi, the intertubular 
cells, analogous to the lacunre, and the intertubular 
substance, analogous to the lamina? of bone. In the 



XXIV INTRODUCTION". 

enamel the greatest departure is observable, but not 
wider than its peculiar function suggests; and it must" 
be remembered, first, that it is the least constant tissue 
of the teeth; secondly, that its chemical composition 
is very much the same as that of the dentine and 
cement, both of which resemble bone. Lastly, the 
analogy is completed in a review of the mode of tooth 
development. Thus, upon a mucous papilla a large 
quantity of gelatinous matter is observable, in which 
certain cells appear. The gelatinous matter resembles 
the incipient cartilage in which ossification begins. 
This papilla is supplied with an artery, which nour- 
ishes its cells, and the cells gradually so develop that 
the older ones are pushed outward and form the 
dentine." 

HOW MADDER AFFECTS THE TEETH. 

John Hunter, one of the most celebrated physiolo- 
gists of the eighteenth century, made many experi- 
ments on, the teeth of different animals, one object 
being to determine whether they were vascular or not. 
His conclusion was that they were not vascular, and 
he founded his belief partly upon the following experi- 
ment (" The Human Teeth," pp. 23-4) : 

" Take, for example, any young animal, as a pig, and 
feed it with madder for three or four weeks; then kill 
it. On examination you will find the following ap- 
pearances: First, if the animal had some parts of its 
teeth formed before the feeding with madder, they 
will be known by their remaining of the natural color; 
but such parts of the teeth as were formed while the 
animal was taking the madder will be of a red color. 
This shows that it is only those parts that were formed 
while the animal was taking the madder that are dyed; 



INTR0DUCTI02^. XXT 

for what were already formed will not be in the least 
tinged. Tills is different in all other bones; for we 
know that any part of a bone which is already formed 
is capable of being dyed with madder, though not so 
fast as th e part that is forming. Therefore, as we know 
that all other bones are vascular, and are thence sus- 
ceptible of the dye, v/e may readily suppose that the 
teeth are not susceptible of it after being once formed. 
But we shall carry this a step further: If you feed a 
pig with madder for some time, and then leave it off 
for a time before killing it, you will find the appear- 
ances as above, with this addition, that all the parts of 
the teeth which were formed after leaving off feeding 
with the madder will be white. Here, then, in some 
teeth we sliall have white, then red, and then white 
again ; and so we shall have the red and white colors 
alternately through the whole tooth.* 

"This experiment shows that a tooth, once tinged, 
does not lose its color. Now, as all other bones that 

*In the concluding part of Moore's " Lalla Rookh" ("The 
Light of the Harem"), the Enchantress says of an herb with the 
unmusical name of " Haschischat ed dab:" 

*' The visions, that oft to worldly eyes 
The glitter of mines mifold, 
Inhabit the mountain -herb, that dyes 
The tooth of the fawn like gold." 

A reference note to the above is as follows : "An herb on 
Mount Libanus, which is said to communicate a yellow golden 
hue to the teeth of the goats and other animals that graze upon 
it. Niebuhr thinks this may be the herb which the Eastern 
alchemists look to as a means of making gold. 'Most of those 
alchemical enthusiasts think themselves sure of success if they 
could but find out the herb which gilds the teeth and gives a yel- 
low color to the flesh of the shcsp that cat it. Even the oil of this 
plant must be of a golden color. It is called HcLSchischat ed dab* 
Father Jerome Dandini, however, asserts that the teeth of the 



XXvi IKTKODUCTIOI^. 

have been tinged lose their color in time, when the 
animal leaves off feeding with the madder (though 
very slowly), and as that dye must be taken into the 
constitution by the absorbents, it seems that the teeth 
are without absorbents as well as other vessels." 

The editor of Hunter's " Treatise," Thomas Bell, 
F.K.S., differed with Hunter about the vascularity of 
the teeth. He thus concludes a note on the above 
quotation : 

" The truth appears to be that the teeth are organ- 
ized bodies, having nerves and absorbent and circula- 
ting vessels, but possessing a low degree of living 
power, and so dense a structure as to exhibit phenom- 
ena, both in their healthy and diseased condition, 
which are very dissimilar from those which are ob- 
served in true osseous structures." ^ 

TRAN'SPLAKTIN'G TEETH. 

The transplanting of teeth, which Dr. Hunter says 
is " similar to the ingrafting of trees," is expatiated 
upon at some length. He then gives an account of a 
case of transplanting which he admits "is not gener- 
ally attended with success," he having " succeeded but 
once out of a great number of trials." It is as follows 
(" The Human Teeth," pp. 100-101) : 

*^ I took a sound tooth from a person's head ; then 

g-oats at Mount Libanus are of a siher color, and adds: 'This 
confirms to me that which I observed in Candia, to wit, that 
the animals that live on Mount Ida eat a certain herb which 
renders their teeth of a golden color, which, according to my 
judgment cannot otherwise proceed than from the mines which 
are under ground.' — Dandlni, Voya'je to Mount Libanus." 



INTRODUCTION". XXMl 

made a wound in a cock's comb, pressed the fang into 
it, and fostcned it with threads. The cock was killed 
some months after, and I injected the head with a very 
minute injection. I then put the coml^ into a weak 
acid. The tooth was softened, and I divided it longi- 
tudinally. Its vessels were well injected, the external 
surface adhering to the comb by vessels similar to the 
union of a tooth with the gum and sockets."* 

* MM. E. Magitot, C. Logros, and C. Robin, have experimented 
in transplanting- the follicles or germs of dogs' teeth, an account 
of which appears in " Comptes Rendus" for 1874. They say : 

" Our experiments comprised 88 grafts, mostly from newly-born 
dogs, but some were 22 and even 58 days old. The animals 
were invariably sacrificed by the pricking of the bulbs, and 
the jaws were opened at once, to lay the follicles bare. One-half 
-of both jaws thus served to supply the grafts, while the other 
was kept for a standard of comparison. The doors on which the 
grafts were applied were usually adults, but sometimes of the 
same age and bearing as those that supplied them. The germs 
were rapidly isolated from the dental gutters, and introduced at 
once. In some instances they were dipped for a few minutes in 
the blood's serum of the sacrificed animal, which was kept by 
the bath (bain-marie) at a temperature of from 30" to 35° C. 
They were introduced under the skin of the nape of the neck, 
the top of the head, and the dorsal and lumbar regions. In 36 
cases the process of application consisted of a simple incision and 
the introduction of the graft 2 or 3 centimeters from the open- 
ing, which was closed by two sutural stitches. In the other 52 
cases a special trocar of an interior diameter of 7 millimeters was 
used, which allowed a swifter and surer transplantation, but it 
did not appear to exert an appreciable influence on the results. 

" Ten grafts were made from newly-born dogs on adult guinea- 
pigs, divided as follows : Whole follicles, 6 ; isolated enamel- 
organs, 3 ; bulb alone, 1. The results were all negative— caused 
by resorption and suppuration— corroborating M. Bert's experi- 
ences in grafis between animals of different zoological orders. 

" The 78 other grafts were made on newly-born, young, and 
adult dogs, and were maintained from 13 to 54 days. The 25 
grafts that remained 54 days resorbed themselves. The experi- 
ments in detail were as follows : 1. Isolated whole follicles, 26. 
2, Follicles with a portion of the maxillary bone, 5. 3. Isolated 



xxviii IKTRODUCTIOI^. 

This appears to prove that Dr. Hunter was right 
when he said that teeth "are capable of uniting with 

bulbs, IG. 4. Bulbs witli a cap of rudimentary dentine, 7. 5. 
Isolated caps of dentine, 4. 6. Isolated enamel-organs, with a 
slired of buccal mucous membrane, 19. 7. Enamel organs, with 
a cap of dentine adhering, 1. The results were : Of the first, 7 
kept alive and grew steadily, except in one instance, in whicli a 
disturbed nutrition brought on tlie formation of globulary den- 
tine and irregular stacks of enamel prisms. The second gave 3 
suppurations and 2 resorptions, again corroborating Mons. Bert's 
experiments. The third gave 3 positive results, in two of wliich 
a new cap of dentine was produced, quite regular, but globulous 
and somewhat altered in its nutrition. The other was without 
enamel. In the fourth experiment the bulbs could not be found ; 
they underwent resorption. When compared with the preced- 
ing experiment, this result is astonishing ; but it should be un- 
derstood that these grafts were maintained from 43 to 54 days. 
Of the fifth a single one kept alive, but without showing any 
growth. It remained stationary 43 days. The sixth invariably 
ended in resorption, notwithstanding we were careful to graft 
the shred of mucous membrane, which supplies the organ with 
nutritive vessels. This result is not surprising when the exces- 
sive frailty of this tissue and its lack of vascularity are consid- 
ered. Some of the negative grafts were either reduced in size, 
being evidently in process of resorption, or underwent the oily 
transformation. Others caused abscesses, and were eliminated. 
"Conclusions. — 1. The grafts gave favorable results only be- 
tween animals of the same zoological order. 2. The isolated 
whole follicles and bulbs may live and develop themselves. 3. 
The transplanting of more or less voluminous portions of jaws 
with the follicles failed through suppuration or resorption. 4. 
The grafts of the enamel-organ, isolated, seem invariably given 
up to resorption. 5. Under certain circumstances the growth is 
regular, with no other difference from that in the normal state 
than a noticeable slowness in the phenomena of evolution. 6. 
Under other circumstances there is trouble in the formation of 
the dentine and enamel, the study of which, however, may be ap- 
plied to the elucidation of the phenomena, still so dark, of tooth 
development. 7. The experiments are an acquisition to the lit- 
erature of and may be compared with other surgical grafts." * 

* For the translation of the above interesting article (from the Reports of 
the French Academy) I am indebted to Monsieur C. Raoux, of New York. 



INTRODUCTIOiq". XXIX 

any part of a living body." Mr. Bell thus concludes 
a note on the above case of transplanting: 

" The experiment has an interest attached to it far 
more important than its having given rise to the tem- 
porary adoption of an objectionable operation. In the 
result of tbis experiment may be found an interesting 
collateral argument in favor of the organized structure 
of the teeth, and their actual living connection with 
the body. The vessels of the tooth, we are told, were 
well injected, and the external surface adhered every- 
where to the comb by vessels. To what purpose are 
these vessels formed, what object can be possibly ful- 
filled by the existence of a vascular pulp in the internal 
cavity, and a vascular periosteum covering the external 
surface — so obviously vascular that it was tcell injected 
from the vessels of a cock's comb, into which it had 
been transplanted— unless they are intended to nourish 
the bony substance of which the tooth consists, and to 
form the medium of its connection with the general 
system ?'' 

Prof. Eichard Owen says (" Odontography," vol. i, 
p. 470) : 

" The saving of material is the least of the benefits 
gained by this tubular structure of the dentine. The 
vitality of the tissue, which Hunter recognized so 
forcibly, but which, being equally convinced of the 
non-vascularity of the tissue, he was unable to explain 

« willing rather to enunciate an apparent paradox or 

be taunted with dilemma, than yield one iota of either 
of his convictions'* — is exphcable by the possible and 

*Prof. Owen quotes from Bell's " notes" in Hunter's "Human 
Teeth." 



XXX INTRODUCTION". 

highly probable fact of a circulation of the colorless 
plasma of the blood through the dentinal tubes. That 
some elementary prolongations of nerve may also be 
continued into these tubes, who can confidently deny ?'' 

As Prof. Owen says the " teeth are always most 
intimately related to the food and habits of the ani- 
mal," it would be interesting and perhaps useful to 
ascertain what effect sugar and other unusual articles 
of diet would have on horses' teeth. In the interest 
of science, experiments appear to be in order. In this 
connection the following paragraph, a part of whicli 
may be found in Prof. William Youatt's work, " The 
Horse " (p. 135), the remainder in '' The Veterinarian," 
is interesting: 

" Surgeon Black, of the Fourteenth Dragoons, says 
til at suo'ar was tried as an article of food durins: the 
Peninsular AVar. Ten horses were selected, each of 
which got eight pounds a day. They took it very 
readily, and their coats became fine, smooth, and 
glossy. They got no corn, and only seven pounds of 
hay instead of twelve, the ordinary allowance. The 
sugar supplied the place of corn so well, that it would 
probably have been given abroad ; but peace came, and 
Avith it corn. The horses returned to their usual diet, 
but several of them became crib-biters. The experi- 
ment was made at tlie Brighton depot, during a period 
of three months. To prevent the sugar from being 
used for other purposes, it was scented with assafetida, 
but the latter did not produce any apparent effect on 
the horses." 



HORSES' TEETH. 



CHAPTER I. 

TOOTH-GERMS (ODONTOGEI^Y). 

Periods at wliicli the Germs are visible in the Fetus. — Dentine 
and Enamel Germs. — A Cement Germ in the Foal. — The 
Horse's Upper Grinders said to be dcA^eloped. from Five 
Germs, the Lower from Four. — Similar development of the 
Human Teeth.— Monsieur Magitot's Researches. 

4 

Furrows in what is subsequently transformed into 
jawbones, in which tooth-germs are, as it were, planted, 
are Nature's first visible preparation for the develop- 
ment of the teeth. According to Prof. William You- 
att, the germs of the temporary teeth are visible seven 
or eight months before the foal is born. Three months 
before its birth the germs of the permanent teeth are 
also visible, a distinct partition separating them from 
the temporary. At this time, according to Veterinary 
Dentist C. D. House, the capsules or bags (also called 
follicles, sacs, &c.), containing the tooth-pnlps* of the 

* Tlie puh^s from which the teeth are developed should not he 
confounded witli tliose of the teeth themselves. Tiie latter, com- 
monly called nerves, on the exposed and pulsating: tops of which 
some human dentists are so inhuman as to put fillings, occupy 
"the central cavity of each tooth, and is a delicate mass of 
connective tissue, cuntuiuing both blood-vessels and nerves." 



33 TOOTH-GERMS. 

future temporary teeth are about the size of small peas. 
They will bear some pressure between the iSngers, the 
indentions spriuging back like those of an India rub- 
ber ball. 

The nature of tooth-germs and the development of 
teeth have been studied with some diligence by scien- 
tific men — Dr. John Hunter, it is said, making the first 
important discoveries in connection with the science. 
The discussion of this interesting and, to students, 
useful subject is left to these men. There is some 
conflict in their views, but it should be remembered 
that the extracts reflect the opinions of men from 
Hunter's time (over a century ago), to 1876. The de- 
velopment of tooth-germs being the same in principle 
(though different in detail) in all m-ammals, the matter 
which follows (as has been said of that in the "Intro- 
duction"), is as applicable to the horse as to man. 

In the Introduction to his " Odontography " (Lon- 
don, 1844), Prof. Eichard Owen says: 

" In the development of a tooth a matrix of equal 
complexity v/as first recognized to be concerned by 
John Hunter, the several parts of this matrix being 
first distinctly indicated in the ^Natural History of 
the Human Teeth.' * * * Hunter has been gen- 
erally regarded by physiologists as being the author of 
tiie theory that the pulp stood to the tooth-bone in the 
relation of a gland to its secretion ; that the formative 
virtue of the pulp resided in its surface ; that the den- 
tine was deposited upon and by the formative or secre- 
tive surface in successive layers, and that the pulp, 
exhausted, as it were, by its secretive aetivit}', dimin- 
ished in size as the formation of the tooth proceeded, 
excepc in certain species, in which it was persistent, 



JOHN HUi^^TER's DISCOVERY. 33 

and maintained an equable secretion of the dentine 
tlirougbout tiie lifetime of the animal This idea of 
the pulp's function has predominated in the minds of 
most subsequent writers on the development of the 
tec til. * ••' * * 

" Three formative organs are developed for the three 
principal or normal deutal tissues, the 'dentinal-pulp/ 
or pulp proper, for the dentine, the 'capsule' for the 
cement, and the 'enamel-pulp' for the enamel. The 
essential fundamental structure of each form.ative 
organ is cellular, but tlie cells differ m each organ, 
and derive their specific characters from the properties 
and metamorphoses of their nucleus, upon which the 
specific microscopical characters of the resulting calci- 
fied substances depend. 

"In the cells of the dcntinal-pulp the nucleus fills 
the parent cell v/ith a progeny of nucleoli before the 
work of calcification begins. In the enamel-pulp the 
nucleus of the cell disappears, like the cytoblast of the 
embryo plant m the formation of most vegetable tis- 
sues. In the cells of the capsule the nucleus neither 
perishes nor propagates, but retains its individuality, 
and gives origin to the mos^; characteristic feature of 
the cement, viz., the radiated cells. 

''The primordial material of each constituent of the 
tooth-matrix is derived from the blood, and special 
arrangements of the blood-vessels preexist to the devel- 
opment and growth of the constituent substances. A 
pencil of capillaries is directed to a particular spot in 
the primitive dentiparous groove, and terminates there 
by a looped network, from which spot a group of nu- 
cleated cells begins to arise in the form of a papilla. 

T^ ^ ^ n* *i* 

"The primary dentinal papilla and its capsule rap- 



34 TOOTH-GEPtMS. 

idly increase by successive additions of nucleated cellSp 
apparently derived from material supplied by the cap- 
illary plexus at the base. The capillaries now begin 
to penetrate the substance of the pulp itself, where 
they present a subparallel or slightly diverging pencil- 
late arrangement, but preserve their looped and retic- 
ulate termination near the apex of the pulp. Fine 
branches of nerves accompany the capillaries, and ter- 
minate also in loops. * * '^ The primary cells and 
the capillary vessels and nerves are imbedded in and 
supported by a homogeneous, minutely subgranular, 
mucilaginous substance, the ' blastema/ * * * The 
vascularity of the dentinal-pulp, and especially the 
rich network of looped capillaries that adorns the 
formative peripheral layer at the period of its func- 
tional activity, have attracted general notice, and have 
been described by Hunter and subsequent authors. By 
most this phenomenon has been regarded as evidence 
of the secreting function of the surface of the pulp, 
and the dentine as an outpouring from that vascular 
surface which was supposed to shrink or withdraw 
from the matter excreted. * * ''' 

" The enamel-pulp differs from the dentinal-pulp at 
its first formation by the more fluid state of its blas- 
tema, and by the fewer and more minute cells which 
it contains. The source of this fluid blastema appears 
to be the free inner vascular surface of the capsule. 
As it approaches the dentinal-pulp the blastema ac- 
quires more consistence by an increased number of its 
granules, and it contains more numerous and larger 
cells. Many of these show a nuclear spot, others a 
nucleus and nucleolus. The spherical nucleolar cells 
in the part of the blastema further from the capsule 
are so numerous as to form an aggregate mass, with a 



DEFII^TING THE BLASTEMA. 35 

small quantity of the condensed blastema in tlie 
minute interspaces left between the cells, which are 
pressed together into hexagonal or polygonal forms. 
* * * The field of the tinal metamorphosis of the 
cells into the molds for the reception of the solidifying 
salts is confined to close contiguity with the surface of 
the dentinal-pulp. Here the cells increase in length, 
lose all trace of their nucleus, and become converted 
into long and slender cylinders, usually pointed at both 
ends, and pressed by mutual contact into a prismatic 
form. These cylinders have the property of imbibing 
the calcareous salts of the enamel from the plasmatic 
fluid, and of comp'icting them in a clear and almost 
crystalline state in their interior. * * * 

"The blastema or fundamental tissue of the capsule 
is, at first, semitransparent and of a pearly or opaline 
color, but IS soon richly ornamented by the plexiform 
distribution of the blood-vessels. As the period of its 
calcification approaches, which is later than that of 
the dentinal-pulp, it becomes denser, and exhibits nu- 
merous nucleated cells. The blastema itself presents 
more evidently a fine cellular or granular structure, in 
which the calcareous salts are impacted in a compara- 
tively clear state, constituting the framework of the 
cemental tissue. The characteristic features of this 
tissue are due to the action of the proper nucleated 
cells upon the salts of the plasma diffused through the 
blastema in which those cells are imbedded, the cells 
being characterized by a single, large, granular nu- 
cleus, which almost fills the clear area of the cell itself. 
If, when the formation of the cement has begun m the 
incisor or molar of a colt, one of the detached specks 
of that substance, with the surrounding and adhering 
part of the inner surface of the capsule in which it is 



26 T00TH-GER3fS. 

imbedded, be examined, the nucleated cells are seen, 
closely aggregated around the calciiied part, in con- 
centric rows, the cells of which are farther apart as 
the rows recede from the field of calcilication. Those 
next the cement rest In cup-shaped cavities in the 
periphery of the calcified part, just as the first calcified 
cells of the thiick cement which covers the crown of a 
complex molar are lodged io cavities on the exterior of 
the enamel. Tliese exterior cavities of the cement are 
formed by centrifugal extension of the calcifying pro- 
cess in the blastema in which the cells are imbedded. 
The calcareous salts penetrate in a clearer and more 
compact state the cavity of the cell, but their progress 
is arrested apparently by the nucleus, whicli maintains 
an irregular area, partly occupied by the salts m a sub- 
granular, opake condition, but chiefly concerned in 
the reception and transit of the plasmatic fluid, which 
enters and escapes by the minute tubes that are sub- 
sequently developed from the nucleolar cavity as calci- 
fication proceeds. 

'' The radiated cells or cavities thus formed are the 
most common characteristic of the cement, but not the 
constant one. The layer of the capsule which sur- 
rounds the crown of the human teeth and of the 
simple teeth of quadrnmana and carnivora, consists 
simply of the granular blastema, y/ithont nucleated 
cells, and the radiated corpuscles are, consequently, not 
developed m the cement which results from its calci- 
fication. In the thicker part of the inflected folds of 
the capsule of the complex teeth of the herbivora, 
traces of the vascularity of that part of the matrix are 
persistent, the blastema calcifying around certain of 
the capillaries, and forming the medullary canals. 
The varieties of these canals are traversed by minute 



PROF. TOMES'S THEORY. 37 

tubules, continued from or communicating with the 
radiated cells. Those tubules, and the more parallel 
ones which traverse the thickness of the cement in 
many mammalia, are the remains of linear series of 
, the minute granules of the blastema. * * '^ 

*•' The general form of the dental matrix and its rela- 
tion w^ith its calcified product, bear a close analogy 
with those of the formative organ of hairs, bristles, and 
other productions of the epidermal system. In these 
the papilla, or pulp, is developed from the external 
skin; in the teeth, from tlie mucous membrane, or 
internal skin." * * * * 

Prof. Charles S. Tomes differs from the views of 
Messrs. Hunter and Owen as to the pulp's secretive 
office, claiming that a tooth is formed by a meta- 
morphosis of its pulp. He says ("Manual of Dental 
Anatoni}^, Human and Comparative/' London, 187G, 
pp. 104-5-G) : 

"' Prior to the beginning of any calcification, there 
is always a special disposition of the soft tissues at the 
spot wliere a tooth is destined to be' formed, and the 
name of ' tooth-germ' is given to those portions of the 
soft tissue which are thus specially arranged. All, or 
a part only, of the soft structures making up a tooth- 
germ become converted into the dental tissue by a 
deposition of salts of lime within their own substance, 
so that an actual conversion of at least some portions 
of the germ into tooth takes place. The tooth is not 
secreted or excreted by the germ, but an actual meta- 
morphosis of the latter takes jolace. 

" The principal tissues, namely, dentine, enamel, and 
cement, are formed from different parts of the tooth- 
germ; hence we are accustomed to speak of the enamel- 



38 TOOTH-GERMS. 

germ and tlie dentine-germ. The existence of a spe- 
cial cement-germ is very doubtful, some writers assert- 
ing, others denying its existence. ^k * * 

" Tootli-gernis are never formed upon the surface, 
but are situated a little distance beneath it, lying in 
some animals at a considerable depth. Every known 
tooth-germ consists in the llrst instance of two por- 
tions, and two only, the enamel and dentine germs. 
These are derived from distinct sources, the former 
being a special development from the epithelium of 
the mouth, the latter from the more deeply lying parts 
of the mucous membrane. Other things, such as a 
tooth-capsule, may be subsequently and secondarily 
formed. The existence of an enamel-organ in an early 
stage is independent of any subsequent formation of 
enamel by its own conversion into a calcified tissue, for 
I have shown it to be found in the germs of teeth 
whicii have no enamel; in fact, in all tooth-germs 
whatever. 

"That part of the tooth-germ destined to become 
dentine is often called the dentine papilla, having 
acquired this name from its papilliform shape; and in 
a certain sense it is true that the enamel-organ is the 
epithelium of the dentine papilla. Yet, although not 
absolutely untrue, such an expression might mislead 
by implying that the enamel organ is a secondary de- 
velopment, whereas its appearance is contemporaneous 
with, if not antecedent to, that of the dentine-germ. 
The most general account that I am able to give of the 
process is, that the deeper layer of the oral epithelium 
sends dow^n into the subjacent tissue a process, the 
shape and structure of whicli is, in most animals, dis- 
tinguishable and characteristic before the dentine- 
germ has taken any definite form. This process en- 



THE ORAL EPITHELIUM. . 39 

larges at its end, and, as seen in section, becomes 
divaricated, so that it bears some resemblance to an 
inverted letter Y ; or it might be better compared to a 
bell-jar with a handle. This constitutes the early stage 
of an enamel-germ, while beneath it, in the mucous 
tissue, the dentmc-germ assumes its papilliform shape. 
The details of the process varying in different animals, 
I will at once proceed to the description of tlie devel- 
opment of teeth in the various groups." 

Prof. Tomes's views of the development of tooth- 
germs in mammals are thus summarized by himself 
(" Philosoi)hical Transactions Eoyal Societ}^' 1875, 
part i, p. 285) : 

"1. There is never, at any stage, an open groove 
from the bottom of which papilia3 rise up. 

"2. That the first recognizable change in the region 
of a forming tooth-germ is a dipping down of a process 
of the oral epithelium, looking, m section transverse 
to the jaw, like a deep simple tubular gland, which 
descends into the submucous tissue, and ultimately 
forms the enamel-organ. 

" 3. That subsequently to the descent of the so-called 
enamel-germ, the changes in the subjacent tissue re- 
sulting in the formation of the dentine papilla take 
place opposite to its end, and not at its surface. I 

"4. That the permanent tooth-germs first appear as 
offshoots from the epithelial process concerned in the 
formation of the deciduous tooth-germ (Kolliker), the 
first permanent molar being derived from a primary 
dipping down (like a deciduous tooth), the second de- 
riving its enamel-germ from the epithelial neck of the 
first, and the third from that of the second (Legros 
and Magi tot)." 



40 TOOTH-GEIIMS. 

Again, in the Society's Transactions for 1876 (p. 2G5), 
Prof. Tomes says: 

'•1. It is desinible to abandon tiie terms * papillary/ 
*i'oliicular,' and 'eruptive' stages, inasmuch as they 
are hypothetical and arbitrary, and correspond to no 
serial conditions verified by observation. 

"3. In all animals a tooth-germ consists primarily 
of two strnctures, and. only two — the dentine-germ 
and the enamel-germ. The simplest tooth-germ never 
comprises anything more. When a capsnTe is devel- 
023ed, it is derived partly from a secondary upgrowth 
of the tissue at the base of the dentine germ, and partly 
from an accidental condensation of the surrounding 
connective tissue. 

'•'3. The existence of an enamel-organ is quite uni- 
versal, and is in no vray dependent on the presence or 
absence of enamel on the completed tooth, although 
the degree to which it is developed has distinct relation 
to the thickness of tlie future enamel. 

"4. So far as my researches go, a stellate reticulum, 
constituting a large bulk of the enamel-organ, is a 
structure confined to the mammalia. (It is absent in 
the armadillo, and I should infer from Mr. Turner's 
description, in the narwhal also). 

"5. As laid down by Profs. Huxley and Kolliker, 
tlie dentine-papilla is beyond all question a dermal 
structure, tlie enamel-organ an epithelial or epidermic 
structure. As I believe it can be shown that the enamel 
is formed by an actual conversion of the cells of the 
enamel-organ, this makes the dentine a dermal and 
the enamel an epidermic structure. 

"6. In teleosts the new enamel-germs are formed 
directly from tlie oral epithelium. They are new for- 
mations, and arise quite independently of any portion 



MONSIEUR CHAUVEAU'S THEORY. 41 

of the germs of the teeth which preceded them. In 
mammals and reptiles, and in some of the batrachia, 
new tooth-germs are developed from portions of their 
predecessors. 

*' 7. In all animals examined the phenomena arc very 
uniform. A process dips in from the oral epithelium, 
often to a great depth, its end becoming transformed 
into an enamel-organ coincidentall}^ with the formation 
of a dentine-papilla beneath it. The differences lie 
rather in such minor details as the extent to" which a 
capsule is developed, and tlierefore no such generali- 
zation as that the teeth of fish in their development 
represent only an earlier stage of the development of 
the teeth of mammalia can be drawn." 

Monsieur A. Chauvean's theory of the development 
of tooth -germs is as follows (" Comparative Anatomy 
of the Domesticated Animals," p. 921) : 

'' The teeth are developed in the interior of a cavity, 
named the dental follicle or sac, by means of tlie ele- 
ments of three germs, one belonging to the dentine, 
another to the enamel, and a third to the cement. The 
dental follicle is an oval cavitj^, with walls composed of 
two layers. The external is fibrous and complete; the 
internal, soft and gelatinous, is allied at the bottom to 
the dentine-germ. The latter is a prominence, which 
is detached from the bottom of the follicle, and has 
the exact shape of the tooth. Its structure comprises, 
in the center, delicate connective tissue, provided with 
vessels and nerves, and on the surface a layer of elon- 
gated cells. At the summit of the follicle, facing the 
dentine-germ, is the enamel-germ. It is exactly ap- 
plied to the dentin al-pulp, which it invests like a caj). 



42 TOOTH-GERMS. 

and is composed of a small mass of mucous connec- 
tive tissue, covered by a layer of cylindrical cells, and 
joined to the buccal epithelium by the guhernaculum 
dentis.'^' According to Monsieur Magitot, the cement- 
organ manifestly exists in the foal. The base of the 
dentine-germ has been found, but it disappears rapidly 
after having performed its function. 

' ^'Developinent of the Dental Follicle. — On the free 
borders of the maxillae, the epithelium of the buccal 
mucous membrane forms an elongated eminence — the 
dental ridge. Below this ridge the epithelium consti- 
tutes a bad, which develops in size, and is sunk in the 
mucous membrane. This is the enamel-germ. It has 
a layer of cylindrical cells on its deep surface, and in 
its center are round cells. After a certain time it is 
only joined to the epithelium, as already said, by a very 
thin line of cells, the guber?iaculum dentis. While this 
enamel-germ grows downward, it covers, by its base, a 
connective bud which rises from the mucous derma. 
The two buds are reciprocally adapted to each other, 

* Concerning the gubernaculum dentis Prof. C. S. Tomes says 
(" Dental Anatomy," p. 135) : " Another structure, once thought 
to be important, but now known to be a mere bundle of dense 
fibrous tissue, is the ' gubernaculum.' The permanent tooth 
sacs, durinor their growth, have become invested by a bony shell, 
which is complete, save at a point near their apices, where there 
is a fora''men. Through this foramen passes a thin fibrous cord, 
very conspicuous when the surrounding bone is broken away, 
which is called the c^ubernaculum, from the notion entertained 
by the older anatomists tliat it was concerned in directing or 
effecting the eruption of the tooth. The j2fubornacula of the 
front y)ormanent tooth sacs perforate the alvolus ana [:)lend with 
the gum behind tlie nocks of the co^vesponamg milk teeth, 
those of the bicuspids uniting wi+h the pcrj^ste^iri o^ ■th«' !»/"«et'lj 
of thoir deciduous predecessors." 



THE DENTIJ^E-GERM TOOTH-SHAPED. 43 

and around them the connective tissue condenses and 
gives rise to the walls of the follicle. It will therefore 
be seen that the enamel-organ is a dependenc}^ of the 
epithelium, and the dentine-organ a production of the 
mncous derma. 

'^Formation of the Dentine, Enamel, and Cement, — 
As before said, the germ of the dentine has exactly the 
form of the fature tooth; consequently the dentine 
which arises from its periphery presents the shape of 
a tooth also. The dentine and enamel are developed 
by the modification of the elements situated at the 
surface of their germs. The dentine is constituted of 
the cells of the germ, which send out ramifying and 
commanicating prolongations — the dentinal fibers — 
and by an intercellular substance, which is impreg- 
nated with calcareous matter, and which, being molded 
around the fibers, forms canaliculi. The enamel is 
derived from the deep cells of its germ, which are 
elongated and prism-shaped, and are calcified in be- 
coming applied to the surface of the dentine. Tlie 
cement is developed at the expense of the walls of the 
follicle, according to the mode of ossification of the 
connective tissue. 

^'Eruption. — As the dentine is formed, the, tooth 
increases in length and presses the enamel-germ up- 
w^ard. The latter, constantly compressed, becomes 
atrophied, and finally disappears wdien the tooth has 
reached the summit of the follicle. In the same way 
the young organ pierces the dental follicle and gum 
and makes its eruption externally. 

"Such is the mode of the development of the tem- 
porary teeth, and the perminent ones are formed in the 
same manner. During the development of the germ 
of the temporary tooth, a bud is seen detaching itself 



44 TOOTH-GERMS. 

from this germ and passing backward, to serve, at a 
later period, in forming the permanent tooth." 

In another part of his work Prof Chauveau says: 

"The follicle in v/hich the incisor teeth are devel- 
oped shows only two papillis. One, for the secretion 
of the dentine, is lodged in the internal cavity of the 
tootli, and is hollowed into a cup-shape at its free ex- 
tremity; the other is contained in the external cul-de- 
sac." 

•^- 

In describing the simplicity of the structure of the 
horse's canine teeth (tushes). Prof. Lecoq says: 

^'The disposition of tlie developing follicle is in har- 
mony v/ith the simplicity of their structure. At the 
bottom there is a simple and conical papilla for the 
internal cavity; on the inner vv'all, a double longitu- 
dinal ridge, on which are molded the ridge and grooves 
on the inner f ice of the tooth." 

Prof William Youatt's theory of the development 
of horses' teeth is unique. He is probably correct 
about the bones or processes being separate, and his 
claim that they are solidified by the cement is certainly 
philosophical ; but he differs from all other authorities 
about the enamel completing the formation of the 
tooth, for it is a well-known fact that a virgin tooth 
is enveloped by cement (its protecting varnish), which 
wears off as soon as the tooth is brought into use. He 
says ("The- Horse," p. 223): 

"A delicate membranous bag, containing a ielly-like 
substance, is fonnd in a little cell withm the jawbone 
of the unborn animal. It assumes by degrees the 
shape of the tooth, and then the jelly begins to change 



GREAT USE OF THE CEMEKT. 



45 




to bony matter. A hard and beautiful crystallization 
is formed on the membrane without, and so we have 
the cutting tooth covered by its enamel. 

'• In the formation of the grinders there are origin- 
ally five membranous bags m the upper jaw and four 
in the lower. The jelly in them 
gives place to bony matter, 
which is supplied by little ves- 
sels, and which is represented 
by the darker portions of the 
cut with central black spots. 
The crystallization of enamel 
may be traced around each of the bags, and there 
would be five distinct bones or teeth but for the fact 
that a third substance is now secreted. (It is repre- 
sented by the white spaces). It is a powerful cement, 
and through its agency the bones are united into one 
.body, thus making one tooth of the five. This being 
done, another coat of enamel spreads over the sides, 
but not the top, and the tooth is completed.'' 

Dr. Robley Dunglison's theory of the development 
of the human teeth is in principle the same as Prof. 
Youatt's tlieory regarding those of the horse. In his 
"Medical Dictionary," article "teeth," he says: 

"The incisor and canine teeth are developed by a 
single point of ossification, the lesser molars by two, 
and the larger by four or five." 

Surgeons M. II. Bouley and P. B. Ferguson believe 
that the teeth are the combined product of the secre- 
tion of the pulp and of the membrane which linos the 
alveolar cavities. They say that the question as to 
whether the sensibility of the teeth is inherent in the 
dental substance itself, or resides exclusively in the 



46 TOOTH-GERMS. 

pulp, is a pliyslological point of which a satisfactory 
solution remains to be given.* 

* Of tlie development of teetli ia the human fetus Monsieur 
E. Magitot says ("Comtes Rendus," 1874): "Seventh Week— 
The epitlielial eminence and epithelial intiecLion of Kolliker 
only may be seen at the edge of the jaw. The superior maxil- 
lary and intermaxillary bones are not united, and the inferior 
maxillary arch contains Meckel's cartilage only, without any 
trace of bone. The epithelial bands (enamel-organs) are succes- 
sively formed in the order of their designation. Ninth — The 
dentine bulb appears in juxtaposition with the downward ex- 
tremity of the enamel -organ. This stage occurs nearly simul- 
taneously for the whole series of temporaiy follicles. Tenth — 
The wall of the follicle detaches itself from the base of the bulb 
and rises up its sides. Fifteenth — The exjithelial band begins 
its transformation into an enamel-organ. The enamel-germ of 
the first -permanent molar may now be seen springing from the 
ej^ithelial inflection. Si-xteenth — The wall of the follicle is 
closed. The epithelial band is broken, and the follicle thencefor- 
ward has no connection with the surface epithelium. The epi- 
thelial bands of the permanent teeth, which are derived from the 
necks of the enamel-organ of tiie corresponding deciduous teeth, 
appear. Svveideenth — Appearance of the cap of dentine of the 
central and lateral incisors ; also the bulb of the first permanent 
molar. Eii/hteenth — Appearance of the dentine caps of the first 
and second molars ; also the wall of the follicle of the perma- 
nent molar. Twentieth — Hight of the dentine caps of the cen- 
tral incisor, lateral incisor, and canine, .059; first and second 
molars, .039. Appearance of dentine organ of permanent teeth, 
and iuclosure of wall and rupture of band of first molar. Twenty- 
fifth — Dentine caps, .07, .054. The permanent follicle walls, 
which ayipeured after the twenty-first week, have acquired a cer- 
tain distincmess. Twenty-eighth — Dentine caps, .093, .078. The 
epithelial germs of the permanent follicles begin their transfor- 
mation into enamel-organs; dentine cap first molar, .003 to .007. 
Tldriy-scconel — Dentine caps, .113, .093. The first permanent 
molar cusps, which form upon the several apices of the dentine 
organ, have coalesced. Thirty -sixth — Dentine caps, .118, .109; 
permanent molar, .004 to .039. Thirty-ninth — Dentine caps, 
.136, .118 ; permanent molar, .039 to .078. The permanent follicle 
walls close. The dentine caps appear one month after birth." 



CHAPTER II. 

THE TEMPORAEY DENTITIOIS". 

Twelve Incisors and Twelve Molars. — Why the Incisors are 
called " Nippers." — The Treatment of Foals Affects Teeth- 
ing.— The Temporary Teeth Absorbed by the Permanent. 
—The Tushes. 

The foaFs temporary teeth (known also as milk or 
deciduous teeth), ure adapted in size and number to 
the capacity of the jaws and the amount and nature 
of the mastication required for its sustenance. There 
are only twenty-four temporary teeth functionally de- 
veloped. They consist of twelve incisors or nippers * 
and twelve molars or grinders, six above and six below 
of each kind. The dental formula is expressed thus: 

Incisors, f — |; molars, f — f =24. 

According to Veterinary Dentist C. D. House, who 
says the care and treatment of foals will affect the 
growth of their 1;eeth as much as they will their gen- 

* Horsemen call the incisor teeth "Nippers." The word ex- 
presses the office they perform, to wit, nipping grass, as well as 
the word "grinder" does in the case of the molars — grinding 
corn. They call the first pair of incisors "central nipi^ers," or 
" centrals," one being on either side of the median line ; the 
second pair are the "dividers," for they stand between the first 
and third pairs; the third pair are called the "corners," from 
their forming the points of the crescent-like figure. 



48 THE TEMPORARY DENTITIOJir. 

enil deyelopment, the foal has no teeth at birth, Na- 
ture providing a thin, membrane-like covering for the 
central incisors as well as the hoofs. In two or three 
days, however, the molars are all cnt. The incisors 
are cnt in pairs, two above and two below. The first 
pair ("^central nippers ") protrude in from three to eight 
days, and attain their growth in about two months. 
The second pair ('-'divider nippers") are cut when the 
foal is five or six weeks old. They also attain their 
growth in about two months. The time of cutting 
the third pair ('-corner nippers") varies. In some 
foals they appear as early ^s the sixth month ; in 
others as late as the ninth. They attain their growth 
in about three months."^ 

The temporary teeth are smaller and whiter and 
have more distinct necks tlian the permanent. Their 
"shining, milky-white color," Monsieur Chauveau 
says, is "due to the thinness or absence of the crusta 
petrosa" (cement). "Their crowns," he says, "are 
finely striated, and not cannular, on the anterior face." 
He also says that " they are not constantly pushed out- 
ward from their cavities, their growth ceasing when 
they begin to be used." This is probably accounted 
for by the fact that the temporary teeth are absorbed 
by the permanent, the proper development of the latter 
apparently requiring the tooth material of the former. 

^ Prof. Owen says : " Monsieur Rousseau, who describes the 
first dentition as b^ing terminated by tlie appearance of (lie lat- 
eral incisors, assigns from the seventh to the tenth month as the 
period of its completion. The appearance of the third deciduous 
incisors, or 'corner nippers,' completes the stage of dentition 
called the ' coil's mouth ' by veterinary authors. The deciduous 
incisors have thinner and more trenchant, normally-shaped 
crowns than those of their permanent succgssoj's." 



SHED OR ABSORBED. 49 

The incisors, which stand in an almost npriglit 
position, are smooth and ronnded on the outer sur- 
face, but grooved on the inner. Their average length, 
including the root, is about an inch, their width 
about half an inch. The molars are about an inch 
and a quarter in length, and nearly an inch in long 
(antero-posterior) diameter. The short (transverse) 
diameter of the upper molars, which is about three- 
fourths of an inch, exceeds that of the lower nearly a 
half. Surgeon John Hughes says that in proportion 
to their length the breadth * of the temporary teeth is 
greater than the permanent. When first cut the in- 
cisor teeth are very sharp ; the outer edges are higher 
than the inner, tlie slant resembling that of a chisel. 
A little wear, however, dulls the teeth, and brings the 
edges to a common level. The contrast between the 
edges of the corner incisors, however, is distinct for 
some time, the outer edge wearing off slowly. 

There is a marked contrast in the appearance of the 
incisors at the age of one year and about the close of 
the second. At the former period they look new and 
fresh, standing close together, while at the latter they 
not only look old and worn, but the development of 
the jaws has caused them to stand apart. Their nar- 
row necks are also conspicuous at two years of age. 

The incisors are shed in the order in which they are 
cut. Nature provides them as they are needed, and 
takes them away so as to cause the least inconvenience 
to the foal. During the shedding of the central inci- 
sors foals have the use of the dividers and corners. 
The permanent centrals are ready for use before the 
dividers arc shed, and the permanent dividers are 

*" Broad til is antcro-posterior diameter; thickness is trans- 
verse diameter." — R. Owen 



50 THE TEMrORARY LE^'TITIO^. 

ready before tlie corners are shed. However, during 
the shedding periods, particularly that of the central 
teeth, foals experience more or less diScnlty in graz- 
ing ; but if they are given a moderate quantity of soft, 
green food, their health will not be impaired, nor will 
they lose much flesh. 

The central incisors are shed when the foal is about 
two years and a half old, the dividers at three and 
a half or four, and the corners afc four and a half or 
five. 

The molars, which Prof. Eichard Ow^en says sooner 
begin to develop roots than the permanent, are shed 
with even less inconvenience to the foal than the in- 
cisors. The fourth grinder, the first permanent tooth 
cut, is ready for use before the first temporary molar 
is shed, and the fi.fth and sixth are ready before the 
second and third are shed. The time of shedding the 
twelve teeth varies somewhat, and the falling off of 
the "caps" of the uppers v/ill pi-ecede those of the 
lower teeth several weeks. Tiie thin shells (caps) that 
fall oil are all that is left of the temporary molars, 
their roots and bodies having been absorbed by the 
permanent teeth, except of course that part which has 
been W'Orn from the crown by attrition. Thus, when 
Nature is let alone, the temporary teeth are absorbed 
rather than shed; but when a shell is loose and in the 
way, it does no harm to remove it. The first molar is 
shed about the end of the second year, the second 
about the end of the third, and the third about the 
end of the fourth. 

Surgeon W. A. Cherry says that the shedding of the 
teeth usually occurs in the Spring. Tiiere is, he says, 
a sufficient interval of time between the shedding of 
the upper and lower molars for the nev/ teeth in tho 



UNFUNCTIOKALLY DEVELOPED CAXINES. 51 

upper jaw to meet the old ones in the lower; sometimes 
tlio respective teeth, when the caps fall olf, are not more 
than the sixteenth of an inch apart. He also says that 
as the temporary teeth wear down they become less 
and less dense. 

While, as before said, it does no harm to remove 
loose shells, the punching out of a pair of incisors, 
Wiiich is sometimes done for the purpose of deception, 
frequently causes serious injury to the permanent 
pair (which should absorb the temporary, and fill the 
space that has become too large for it), not to mention 
the interference with grazing. The temporary teetli are 
often broken oR at the neck and the sockets injured; 
tliis sometimes causes the permanent to grow irregu- 
larly, which in the case of the liorse is a very serious 
matter, for if the permanent teeth do not meet, and are 
consequently not worn off by attrition, their growth, 
which continues throughout life, will cause trouble. 
There are cases, however, suck as abnormal groAvths, 
accidents, &c., in which it is necessary to remove the 
temporary tooth, but the forceps only should be used. 
When the teeth have been removed for the purpose of 
deception, the object is to make it appear that tliey 
Jiave been slied, and that the animal is older than it 
reallv is. 

Veterinary authors, as a rule, do not mention the 
temporary tushes. A few odontologists, however, liave 
described them. Prof. Owen ('•'Odontography," vol. i, 
p. 580) says "^the small deciduous canine^ is cut about 
the sixth month, at the time the third or cnmer inci- 
sors are cut. Tlie lower tush, owing to its diminutive 
size, and its being so close to the incisor, "is shed 
almost as soon as tlie crown of the contiguous incisor 
is in full place, being carried out by the same move- 



52 THE TEMPORARY DEKTITIOIT. 

ment." Bojanns,* Prof. Owen says, first "drew the 
attention of vetorinary authors to it by his memoir 
* De Dentibus Caninis Caclucis/ &c. Bojiinus never 
found the lower deciduous canine retained beyond the 
first year. The deciduous canine of the u[)per jaw, 
being- developed at a short distance behind the incisors, 
is less disturbed by the eruption of the outer incisor, 
but is nevertheless shed in the course of the second 
year. The deciduous canines appear from Camper's f 
observations to retain their place longer in the zebra 
than in the horse." 

Monsieur Lecoq says: 

" The canine teeth are not shed, and grow but once. 
Some veterinarians, and among them Forthomme and 
Rigot, witnessed instances in which they were replaced ; 
but the very rare exceptions cannot make us look upon 
these teeth as liable to be renewed. We must not, 
however, confound with these exceptionable cases the 
shedding of a small sp*icula or point, which, in the 
majority of horses, precedes the eruption of the real 
tusks." 

Prof. C. S. Tomes says: 

" The milk teeth of all the ungulata are very com- 
plete, and are retained late. They resemble the per- 
manent teeth in general character, but the canines of 
the horse, as might have been expected — their greater 
development in the male being a sexual character — are 
rudimentary in the milk dentition." 

* " Nova Acta Nat. Curios., torn, xii, part ii, p. 697. 1825." 
f " CEuvres de Pierre Camper. Paris, 1805." 



CHAPTER III. 

THE PERMANENT DENTITION. 

Distinction between Premolars and Molars. — The Bow-like In- 
cisors. — Contrasts between tlie Upper and Lower Grinders, 
and the Rows formed by them. — The Incisors saved from 
Friction. — Horses' Teeth compared with those of other An- 
imals. — Measurements. — Time's Changes. — Growth during 
Life. 

The Permanent Teeth, owing to their increased size 
and number, are as well adapted to the needs of the 
horse as the temporary are to the foal. In the males 
forty teeth are functionally develoj^ed ;* in the feaiales 
thirty-six, the latter, as a rule, having no canine teeth. 
However, their rudiments exist in the jaw\s, and some- 
times, especially in old age, protrude. Of the forty 
teeth in the male horse there are twelve incisors, four 
canines or tushes (also called cannon or bridle teeth), 
twelve premolars,! and twelve molars. The dental 
formula is expressed thus : 

-^•J 3 3 ^ '^v 1 1) ^' -w^v 3^ — 3^7 ^^^-} ^ — 3 — '*^* 

* The teeth that are not functionally developed are treated of 
in tlie chai)ter entitled " Remnant Teeth." 

f "Premolars are teeth in front of the molars ; they usually 
differ from them by beinjr smaller and more simple in form, and 
in most animals have displaced deciduous predecessors. But 
they are not always smaller nor simpler in form (e. g., the 



54 THE PERMANENT DElls'TITIOl^r. 

The incisors and premolars absorb and replace the 
entire temporary dentition, except the shells or caps 
described in the preceding chapter, but tbe canines 
and molars are cut through the gums. 

In Yeterinary works, as a rule, no distinction is made 
between a premolar and a molar, the twenty-four back 
teeth being called either molars or grinders. Prof. 
0. S. Tomes says the premolars and mofers "are very 
similar to one another in shape, size, and in the pat- 
tern of their grinding surface." There is a difference, 
however, between the respective teeth, and naturalists 
make a distinction. The premolars (the three first 
back teeth), whicli replace the temporary molars, are 
slightly larger than the molars (the three last back 
teeth). They have besides a backward inclination, 
v/hile the molars incline forward ; the respective teeth 
are thus set toivard one another. Both kinds are 
properly called grinders. 

The permanent teeth arc cut in pairs, two in either 
jaw, the upper teeth preceding the lower from one to 
two weeks. In the cutting of the canines, however, 
the reverse is the rule, for the lovvTr teeth precede the 
upper. About a year's time elapses betv/een the cut- 
ting of the respective pairs of teeth ; that is, when the 
central incisors are cut, it v/ill be about a year before 
the dividers will emerge. The rule is applicable to 
the premolars and molars also, but the case is different, 
for tvv^enty-four of these teeth have to be cut during 

horse) ; nor do tliey always displace deciduous predecessors 
{e. g., til oy do not all do so in the marsupials) ; so that this defi- 
nition is not absolutely precise. Still, as a matter of practice, 
it is usually easy to dJstin^Tiish tiie premolars, and tlie division 
into premolars and molars is useful." — C 8, Tomes, "Dental 
Anatomy," &c., p. S5S. 



TIME 0? CUTTIJTG. 55 

the same period of time that the twelve incisors are 
cut. A permanent tootli attains its growth in about a 
year. 

Accordhig to the best authorities, the molar and 
canine teeth are cut at tlie following periods: The 
first molars (in veterinary works they are called the 
fourth, because the three premolars come in front of 
them) are the first permanent teeth cut. The time of 
their cutting varies, for the foal's jaws must be suffi- 
ciently developed to afford fliem room, notwitiistand- 
ing they are usually the smallest of the six back teeth. 
They are cut about the beginning of the second year, 
and are generally ready for use by the time the foal is 
two years old. The second molars are cut at about 
tlie age of two years, and are therefore fully developed 
by the end of the third year. The third pairs, the last 
of the molars, and consequently the most posterior of 
all the teeth, are sometimes cut as early as the third 
year, in which case they would be developed by the end 
of the third or the beginning of the fourth year. The 
time, however, may be prolonged six months or more. 
The canine teeth (tushes) emerge at or near the be- 
ginning of the fourth year.^- 

The time of the appearance of the incisors and pre- 
molars has already been indicated in the preceding 
ch.apter. However, the following extract from Prof 
Owen's "Odontography" is appropriate in this place, 
a=' it throws further light on the subject, and to some 
extent agrees with the dates already given: 

'■The fir>t true permanent molar appears between 
the ebvcnth and thirbcenth months. The second fol- 

•■• For further particulars concornin<T tlio tuslies the reader iB 
referreJ to the succeeding chapto;-. 



56 THE PEBMAJS'Eiq-T DEJ^TITIOJ^. 

lows between tlie fourteenth and twentieth months. 
The crowns of the premolar and the last true molar 
are now advancing in the closed sockets of reserve. 
The first premolar displaces the second,* and nsually 
at the same time the very small deciduous molar, at 
from two years to two years and a half old. The first 
permanent incisor rises above the gum between two 
years and a half and three years. At the same period 
the second premolar pushes out the third deciduous 
molar. The last premolar displaces the last deciduous 
molar about the completion of the fourth year, and 
the appearance above the gum of the last true molar 
is usually anterior to this. The second incisor pushes 
out its predecessor between three and a half and four 
years. The small persistent canine or tusk, contrary 
to the usual rule, next follows, its development having 
received no cheek by the retention of its rudimental 
predecessor. Its appearance indicates the age of four 
years ; but it sometimes appears earlier, rarely later. 
The third incisor pushes out the deciduous one about 
the fifth year, but is seldom completely in place before 
the horse is five years and a half old. The third j^re- 
molars are then usually on a level with the other 
grinders." 

On the completion of the fifth year a male foal is 
called a horse, a female or filly foal a mare. The teeth, 
however, are not all fully developed before the sixth 
year, and the roots of the grinders do not begin to 

* To prevent confusion, it sliould "be understood that Prof. 
OAven calls tlie "very small deciduous molar" liere referred to 
the first deciduous molar, notwithstanding it is not functionally 
developed. Hence, as it has no successor, the first premolar dis- 
places the second deciduous molar, the s3cond premohir the third 
deciduous mola.r, and the third, the fouxtK 



THE INCISORS ADAPTED FOR GRAZING. 



57 



grow till about the seventh year, being, to use Prof. 
Owen's words, "implanted, in the. socket by an undi- 
vided base." 

The incisor teeth, which will average about two 
inches and a quarter in length, are characterized by 
distinct curvatures, the outer sur- 
fiice, according to Surgeon John 
Hughes, forming a third of a cir- 
cle, the inner a fifth. Were a string 
drawn from the crown of one of 
these teeth to the apex of the 
root, the figure would resemble a 
bow. The upper teeth are larger 
than the lower, and there is a dif- 
ference in^size of the respective 
teeth in both jaws, the centrals 
being larger than the dividers, 
and the dividers larger than the 
corners. 

The incisors meet edge to edge, 
being thus admirably adapted for 
the purposes of grazing, and at ^ ^i,gi„ i„eisor tooth -. pos. 
the age of six years the bodies are tenor face.-c^«.e««. 
nearly perpendicular one to the other. They form 
nearly semicircular figures, and, when the mouth is 
closed, present a rounded outer surface. 

" The incisors," says Prof. Owen, "if found detached, 
recent or fossil, are distinguishable from those of the 
ruminants by their greater curvature, and from those 
of all other animals by the fold of enamel which pen- 
etrates the body of the crown, from its broad, flat sum- 
mit, like the inverted finger of a glove." 

The fold of enamel, which is commonly called the 
<«mark," but which is also known as the infundibulum, 




58 THE PERMANENT DEKTITlON. 

central enamel, &c., according to Surgeon J. Hughes's 
mGasurements, penetrates the lower centrals to the 
depth of from three-iifths to seven-tenths of an inch ; 
the dividers from seven-tenths to four-fifths, and the 
corners from one-half to three-fifths. It penetrates 
the upper centrals from one inch and a tenth to one 
and a fifth ; the dividers from one and a fifth to one 
and a fourth, and the corners from four-fifths to nearly 
an inch. Prof. Youatt says the grinder teeth have 
each two iniundibula, v/hich penetrate to their roots. 

The followhig is Prof. A. Chauveau's description of 
the incisor teeth ("The Comparative Anatomy of the 
Domesticated Animals/' Fleming's trans., p. 349) : 

" The general form of the incisors is that of a tri- 
faced pyramid, presenting an incurvation f^diose con- 
cavity is toward the mouth. Tiie base of this pyra- 
mid, the crown of the tooth, is flattened before and 
behind. The summit or extremity of the fang, is, on 
the contrary, depressed on both sides. The shaft of 
the pyramid presents at diiierent points of its hight, a 
series of intermediate conformations, which are utilized 
as indications of age, tlie continual growth of the teeth 
bringing each of them in succession to the frictional 
surface of the crown. 

" Examined in a young tooth, but one that has com- 
pleted its evolution, the free portion presents the fol- 
lowing characteristics : An anterior face, indented by 
a slight longitudinal groove, v^^hich is prolonged to 
the root ; a posterior face, rounded from side to side; 
two borders, of which the internal is always thicker 
than the external ; and, lastly, the surface of friction. 
The latter does not exist in a tooth that has not been 
used, but in its stead are two sharp margins, circum- 



THE TWO mXGS OP E]SrAMEL. 59 

scribing a cavitj^ named the external de?ital cavity, or, 
better, infundiljulum. This cavity terminates by a 
conical cul-de sac, which descends more or less deeply 
into the snbstance of the tooth. The margins are 
designated the anterior and posterior. The latter, less 
elevated than the former, is cut by one or more 
notches, which arc always deepest in the corner teeth. 
It is by the wear of these margins that the surface of 
fi'iction is formed, and in the center of which the in- 
i'undibulum persists during a certain period of time. 

*•' The fang is perforated l)y a single aperture, through 
w^hich the pulp of the tooth penetrates into the inter- 
nal cavity. 

"In the composition of the incisor teeth are found 
tlie three fundamental substances of the dental organ. 
The dentine envelops the pulp cavity. Dentine is de- 
posited in this cavity after the complete evolution of 
the tooth to replace the atrophied pulp, the yellow tint 
of which distinguishes it from the dentine of the first 
Ibrmation. It forms on the table of the tooth the 
mark designated by Girard the dentinal star. 

" The enamel covers the dentine, not only on its free 
portion, but also on the roots; it does not extend, 
liowever, to their extremities. It is doubled into the 
external dental cavity, lining it throughout; and when 
the surface of friction is established, a ring of enamel 
may be seen surrounding it, and an internal ring cir- 
cumscribing the infundibulum. The first circle is 
called the encircling enameU the second the centred 
enamel. In the virgin tooth the central enamel is 
continuous with the external enamel, and passes over 
the border wliich circumscribes the entrance to the 
infundibulum. 

'•The cement is applied over the enamel like a pro- 



CO TtlE PEEMAI^EKT DENTITION. 

tecting varnish, but is not everywhere of the same 
thickness. On the salient portions it is extremely 
thin, and the friction caused by the tbod, the lips, and 
the tongne soon wears it away altogether. It is more 
abundant in depressed situations, as in the longitudi- 
nal groove on the anterior f?ice of the tooth, and par- 
ticularly at the bottom of the infundibulum. The 
quantity accumulated in this cul-de-sac is not, how- 
ever, always the same. We have seen it almost null, 
and on the other hand, we possess an incisor unworn, 
or nearly so, in which the cavity is almost entirely 
obstructed by it. We are not aware that, up to the 
present time, any account has been taken of these dif- 
ferences in calculating the progress of wear ; but it is 
manifest that they shorten or prolong the time re- 
quired for the effacement of the infundibulum." 

The grinder teetli, the horse's millstones, present 
various and interesting contrasts. They are sepa- 
rated from the incisors by a space that will average 
about four inches in extent, the sharp-pointed tushes 
(in males) only intervening. The space between the 
grinders and tushes is called the diastema (place for 
the bit). The upper grinders, except the first and 
last, are nearly quadrangular in form. The first and 
last, which exceed the others about a third of an inch 
in antero-posterior (front to rear) diameter, terminate 
in obtuse angles, which are far more pronounced on 
the inner than on the outer surface, thus affording the 
tongue fuller and freer pla}', without the danger of its 
being lacerated, as would be the case wxre the angles 
sharp. The form of the lower grinders, with the same 
exceptions in the case of the first and last, is nearly 
rectangular; their antero-posterior diameter is the 



THE HORSE'S DIIlTlN'ER TABLES. Gl 

same as that of tlic upper teeth, but their transverse 
diameter is nearly a half less. . 

The broad crowns of the upper teeth form what are 
called by veterinarians " tables," wdaereon the food is 
ground or kneaded by the narrow-crowned opposite 
grinders, the lateral movement of the lower jaw ena- 
bling the latter teeth to pass over the entire extent of 
the former. 

Tlie crown surfVices of the upper and lower rows are 
slanting instead of level, the former slanting inward, 
the latter outward. The inclined-planes are thus in 
perfect opposition, and yet in perfect harmony, for they 
facilitate the lateral and semicircular movement of the 
lower jaw during mastication. 

The tigures formed by the upper and lower rows of 
grinders, aside from the difference in their thickness, 
are very dissimilar. The upper rows are slightly con- 
cave, and converge in conformity to the narrowing of 
the jaws; the space between the sixth grinders averag-es 
about two inches and four-fifths, while that between 
the first is about two inches. The lower rows form 
regular but oblique lines, which also converge, like the 
sides of a hopper, in conformity to the narrowing of 
the jaw^s, the space between tlie two sixth grinders and 
the two first averaging respectively two inches and a 
half and one inch and a half. Thus, when the mouth 
is closed, the lower teeth in the region of the sixth 
grinders scarcely cover a third of the crown surface of 
the upper teeth, while those in the region of the first 
barely lap their inner edges. This apparent structural 
defect is overcome by the lateral movement of the 
lower jaw, which, owing to the fact that it increases 
in proportion to the distance from its hinge-like joint 
in the region of the temporal bone and zygomatic 



62 THE PERMANENT DENTITION. 

arch,* is greater in the region of the first grinders 
than in that of the sixth. Therefore it will be per- 
ceived that it is only alternately that the rows are used 
in the performance of the masticatory function, and 
that v/ere the grinders in exact apposition (edge to 
edge), the lateral and semicircular movement of the 
lower jaw would be as awkward and unnatural in the 
case of the horse as the same movement would be in a 
human being. 

There are still other contrasts between the grinders. 
According to Surgeons M. H. Bouley and P. B. Fergu- 
son, the upper teeth are slightly convex, the lower 
slightly concave. Again, according to Charles D. 
House, the outer surface of the upper grinders is pro- 
vided with a coat of enamel twice as thick as that of 
the inner, "while the reverse is the case with the lower 
teeth. There is design in this provision of Nature 
(notwithstanding Mr. House says it is inexplicable), 
for the projecting edges receive that which they re- 
quire, to wit, strength in proportion to their hight; 
otlierwi^e they w^ould be easily broken off. As the 

* Prof. Youatt says ; " The branclies of tlie lower jaw termi- 
nate in two processes, the coracoid (beak-like), and the condy- 
loid (rounded). The coracoid passes under the zy<Tomatic arch, 
the temporal muscle being inserted into it and wrapped round 
it. The condyloid is receiv^ed into the glenoid (shallow) cavity 
of tlie temporal bone, at the base of the zygomatic arch, and 
forms the joint on which the lower jaw moves. The joint ad- 
mits of a hinge-like motion, which is the action of the jaw in 
nipping the herbage and seizing the corn. The corn, however, 
must be ground ; bruising and champing it are not sufficient for 
the purposes of digestion. It must be put into a mill. It is put 
into a mill, and as perfect a one as imagination can conceive. 
The construction of the glenoid cavity gives the required lateral 
or o rinding motion." 



THE GRINDERS THEIR OWN WHETSTONES. 63 

lower edges have only about lialf the hight of the up- 
per, they do not require more tlian half the quantity 
of enamel to strengthen them. Another use of this 
unequal disposition of enamel is its tendency, by its 
wear, to preserve the slant of the respective crown sur- 
faces. Further, the dentine, which hlls tlie interspaces 
between the folds or ridges of enamel, being softer 
than the enamel, wears out faster, thus keeping the 
ridges sharp.* The grinders are therefore, owing to 
this "interblending of the dental tissues," their own 
whetstones as well as the horse's millstones. 

Some writers, even of the present day, deny that the 
enamel penetrates to the interior of the grinders; but 
the fact that it does was established by John Hunter 
over a century ago, and a cut of a section of a horse's 
grinder (slightly magnified) showing the enamel folds, 

* Pr.^f. R. Owon illustrates the above principlo in the Intro- 
duction to his " Odontography," paj^e 26. He sa3'S: "It(tliG 
enamel) sometimes forms only a partial investment of tlie crown, 
as in the molar teeth of the iguanodon, the canine teeth of the 
hog and liippoi^otamus, and the incisor3 of the Rodentia. In 
these the enamel is placed only on the front of the tooth, but is 
continued along a great part of the invested base, which is never 
contracted into one or divided into more fangs, so that the char- 
acter of the crown of tlie tootli is maintained throughout its 
extent as rej^ards both its shape and structure. The partial 
application of the enamel operates in maintaining a sharp edge 
upon the exposed and worn end of the tootli precisely as the 
hard steel keeps up the outer cutting edge of tlie chisel by being 
welded a<Tainst an inner plate of softer iron." 

Prof. C. S. Tomes, speaking of the grinder teeth of the horse, 
says : " As each ridge and pillar of the tooth consists of dentine 
bordered by enamel, and the arrangement of the ridges and pil- 
lars is complex, and as, moreover, cementum fJlrJ up the inter- 
spaces, it is obvious that an efficient rough griiuiing surface will 
bo preserved by tlie unequal wear of the several tissues." 



64 THE PERMANEN"T DEJ^TTITIO^q". 

may be found in his "I^atnral History of the Human 
Teeth." 

The formation of the enamel is thus described by 
Prof. Bouley and Surgeon Ferguson ("Veterinarian," 
1844) : 

"In the grinder teeth the enamel may be said to 
resemble a little ribbon, which forms, in refolding 
many times upon itself in the interior of the tootli, a 
succession of undulating planes, and constitutes the 
hard external envelop of the cubic mass of the organ. 
An idea of this disposition may be formed on examin- 
ing a tooth which is not yet cut, but which is ready to 
be cut. Those that have been worn, present on their 
crowns, besides the undulating lines of the enamel 
envelop, a sucaession of reliefs, salient and sinuous, of 
the substance of the enamel, which are nothing else 
than the free borders of this folded ribbon. It is in 
the intervals of the folds of euLimel that is deposited 
the ivory-colored substance (dentine), which renders 
the tooth a solid mass when it has attained its full 
growth." 

Prof. Eichard Owen, one of the first odontologists 
of the age, in whose numerous works descriptions of 
many kinds of teeth may be found, has paid a fair 
share of attention to the study of horses' teeth, both 
recent and fossil. His description of the grinders and 
comparisons with the teeth of other animals are too 
interesting to be omitted here, and render any apology 
for the few repetitions of facts already given unneces- 
sary. He sa3^s (-'^ Odontograph}^/' vol. i, p. 572): 

"The horse will yield us the first example of the 
dentition of the hoofed quadrupeds with toes in un- 



ANOPLOTIIERES, TLUMII^'AXTS, AXD TAPIRS. 05 

even number, because it offers in tliis part of its organ- 
ization some transitional features between the dental 
cbaracters of the ty[)ical members of the isodactyle 
and of those of tlie anisodactyle unguhita. 

"All the kinds of teeth are retained and in almost 
normal numbers in both jaws, with as little unequal 
or excessive development as in the anoplothere,* but 
the prolongation of the slender jaws carries the canines 
and incisors to some distance from the grinders, and cre- 
ates a long diastema, as in the ruminants f and tapirs. J 

* " The anoplothere was one of the earliest forms of hoofed 
quadrupeds introduced upon the surface of this earth, and it is 
cliaracterized by the most complete system of dentition. It not 
only possessed incisors and canines in both jaws, but they were 
so equally developed that they formed one unbroken series with 
the premolars and molars, which character is now found only 
in the human ftpccies. The dental formula is : I.. 3—8, 3—3 ; 
C, 1-1, 1-1 ; P. M., 4-4, 4-4; M., 3-3, 3-3=:44. The An- 
oplothere Commune was the size of an ass, and, with the other 
species of the extinct genus, had a cloven hoof, like the Rumi- 
nants, but the division extended throuofh the metacarpus and 
metatarsus. The anoplothere Avas an animal of aquatic habits, 
and had a very long- and strong tail, which Cuvier conjectures 
to have been used like that of the otter in swimming." — Owen. 

f " The ordinary dental formula of the Ruminantia is : I. 
(upper jaw), 0-0, (lower jaw), 3-3 ; C, 0-0, 1-1 ; P. M., 3-3, 
3—3 ; M., 3-3, 3—3=32. The antelopes, the sheep, and the 
ox, which are collectively designated the 'hollow-horned ' rumi- 
nants, present this formula. It likewise characterizes many of 
the ' solid-horned ' ruminants, or the deer tribe, the exceptions 
having canine teeth in the upper jaw in the male sex, and some- 
times also in the female, though they are always smaller in the 
latter." — Oicen. 

X " The dental formula of the tapir is : I., 3-3. 3-3 ; C, 1-1, 
1-1 ; P. M., 4-3, 4-3 ; M., 3-3, Z-^^A%"—Owcn. 

It is noteworthy that the dentition of the tapir corresponds 
precisely in number with that of the horse, providM the latter's 



G6 THE PEEMAXEXT DEXTITIO:^'. 

" The upper grinder teeth present a modification of 
the complex structure intermediate between the aoo- 
X>iotlierian and ruminant patterns. The crown is 
cubical, but is impressed on the outer surface by two 
wide and deep longitudinal channels. It is penetrated 
from within by a valley, v/liicli enters obliquely from 
behind forward. This is crt.issed by two crescentic 
Talleys, which soon become insulated, as in the camel ;^' 
but a large internal lobe, at the end of the oblique val- 
ley, presents more of the anoplotherian proportions 
than is shown by any ruminant. It is at first distinct ; 
but althongh it soou becomes confluent with the ante- 
rior lobe iu the existing species of the horse, it con- 
tinued distinct much longer., and with more of the con- 
ical or columnar form, in the primigenial horse of the 
miocene tertiary period. 

''The grinder teeth of the horsc^, Ouvierf remarks, 



Remnant teeth are counted ; and, besides, the odd teetli in both 
animals appear in the upper jaw. Prof. T. H. Huxley says : 
" Deepen the valley, Increase the curvature of the (outer) wall 
and lam'inoe (transverse ridg-es); give the latter a more directly 
backward slope; cause them to develop accessory ridges and 
l)illars, and the upper molars of the tapir will pass through the 
structure of that of the rhinoceros to that of the horse." 

*"The dental formula of the camel is: I, 1-3, 1-3; M., 
Q—Q, 6—6=32. The anterior molars are conical. They are 
separated from the posterior molars, and are sometimes regarded 
as canines. The upper incisors are also conical, compressed, 
somewhat curved, resembling canines, and are used for tearing 
up the hard and strong plants of Ihe desert, on which the ani- 
mal usually feeds." — Amc^^'can Cyclopedia. 

f A French naturalist. Died May 13, 1883. " He is regarded 
as the founder of the science of comparative anatomy, and his 
knowledge of the science was such tliat a bone or a small frag- 
ment of a fossil animal enabled him to determine the order, and 



THE HORSE AN"D THE RHINOCEROS. 67 

have a closer analogy with those of the rhinoceros* 
than might at first be. supposed. The anterior cres- 
centic enamel represents the termination of the prin- 
cipal or obli(|ue valley, which is cut olf by a bridge of 
dentine analogous to that in the leptorhine rhinoceros. 
The posterior crescentic island is a further develop- 
ment of the fclds in the rhinoceros' molar, but is much 
earlier insulated in the horse. 

*'In the lower jaw the same analogies maybe traced. 
The teeth, on the outer side, are divided into two 
convex lobes by a median longitudinal fissure; on the 
inner side they present three principal unequal convex 
ridges, and an anterior and posterior narrower ridge. 
The crown of the grinder is penetrated from the inner 
side by deeper and more complex folds than in the 
anoplothere, and still more so than in the rhinoceros 



even genus, to which it belonged. The time of Cuvier marks 
the opening of a new epoch in comparative anatomy. He ap- 
plied this science to natural history, physiology, and to the study 
of fossils The first edition of "Lccons d'Anatomie Comparee" 
appeared about the beginning of the i^resent century, and the 
second was the last work upon v/hich Cuvier labored. For 
more than thirty years he had collected an immense amount of 
facts and materials, which are partly embodied in this book. It 
is a monument of patient industry, a model in arrangement, and 
a mine of knowledge, of whicli all observers since have availed 
themselves. " — American Cyclopedia. 

" " The essential characteristics of the dentition of the genua 
rhinoceros are to be found in the form and structure of the 
molar teeth. They diifer essentially from those of the horse by 
being implanted by distinct roo*p. The normal dental formula 
of the molar series is: P. M.. 4-4, 4-4; M.. 3-3, 3-3:=28. 
There are no canines. As to the incisors, the species vary, not 
only in regard to their form and proportions, but also their ex- 
istence." — Oioen. 



68 THE PERMAKEXT DENTITION". 

and iDixleothere. * The anterior valley between the nar- 
row ridge and the first principal internal column ex- 
pands into a snbcrescentic fold. The second is a short, 
simple fold, and terminates opposite that which pene- 
trates tlie tooth from the outer side. The third inner 
fold expands in the posterior lobe of the tooth like the 
first, and two short folds partially detach a small ac- 
cessory lobe at the posterior part of the crown. All 
the valleys, fissures, or folds, in both the npper and the 
lower grinders, are lined by enamel, which also coats 
the whole exterior surface of the crown. 

"The character by which horses' grinders may best 
be distino-uished from the teeth of other herbivora cor- 
responding with thom in size, is the great length of 
the tooth before it divides into fangs. This division, 
indeed, does not begin to take place nntil much of 
tlie crown has been worn away. Thus, except in old 
horses, a considerable proportion of the whole of the 
tooth is implanted in the socket by an nndivided base. 
This is slightly curved in the upper grinders. 

"The deciduous molars have shorter bodies than the 
permanent, and sooner begin to develop roots. They 
may be distinguished from the rooted molar of a rumi- 
nant, as may also their permanent successors with 
roots, by their form and the pattern of their grinding 
surface. The latter may be a little changed by tiie 
partial obliteration of its enamel folds, but it gen- 
erally retains enough of its character to show the 
distinction." 

* " The species of paleotlierium, wlucli appear to have accom- 
panied the anoplotheres in the first introduction of hoofed quad- 
rupeds upon this planet, v/ere characterized by the same com- 
plete dental formula, namely, forty-four functionally developed 
teeth." — Owen. 



AKISTOTLE'S MISTAKE. 69 

Monsieur Lecoq's description of the grinder teeth, 
like the one just quoted, is a contribution to dental 
science. The repetition of facts ah'eady given is off- 
set by its additional facts, and its historical informa- 
tion is as interesting as are Prof. Owen's comparisons. 
It is as follows ('' Traite de I'Extcrieur du Cheval et des 
Princii^aux Animaux Domestiques'') : 

" It w^as believed for a long time that the grinders of 
Solipeds were all persistent teeth. This error, founded 
on the authority of Aristotle, w^as so deeply rooted that, 
although Ruini, toward the end of the Sixteentli cen- 
tury, had discovered the existence of two temporary 
molars, Bourgelat did not believe it when he founded 
the French veterinary schools, and was only convinced 
when Tenon proved hy specimens, in 1770, that the 
first three are deciduous. 

" Generally considered, the grinder arcades have not 
the same disposition in both jaws. Wider apart in the 
superior one, they form a slight curve, whose convexity 
is outward. In the inferior jaw, on the contrary, the 
two arcades separate in the form of a Y toward the back 
of the mouth. Instead of coming in contact by level 
surfaces, the grinders meet by inclined-planes. In the 
lower jaw the internal border is higher than the exter- 
nal, while the reverse is the rule in the upper. This 
circumstance prevents the lateral movement of the 
lower jaw taking place without separation of the inci- 
sors, and thus saves them from friction. 

" Like the incisors, each grinder presents for study 
a free and a fixed portion. The free portion (the body), 
nearly square in the upper grinders, broader than 
thick in the hnver, sliows at the external surface of the 
former two longitudinal grooves, the anterior of which 



70 THE PERMAKEKT DENTITIOIS". 

is the deeper, both being continued on the incased 
poi'tion. This is not the case with the lower grinders, 
"which have but one narrow and frequently indistinct 
groove. The internal surfiice, in both javv\s, presents 
only one groove, and that but lirtlj marked. It is 
placed backward in tlie upper teeth, and is most ap- 
parent toward the rout. The anterior and posterior 
faces of the respective teeth, wliieh are in coniaet with 
each other, are nearly level, but at the extremities of 
the arcades the isolated faces are converted into a nar- 
ro^v border. 

" The grinders are separated from each other by their 
imbedded portion, particularly at the extremities of 
the arcades, an arrangement v/hich strengthens them 
by tlirow^ing the strain put upon the terminal teeth 
toward the riiiddle of the line. They exhibit a variety 
of roots. In the first and last, either above or below% 
there are three, while the intermediate teeth have four 
in the upper jaw, and only two in- the lower. The 
root, if examined a short time after the eruption of 
the free portion, looks only like the shaft of the latter, 
without any appoarancc of fangs, and has internally 
a wide cavity. It is not until the tooth begins to be 
l^ushed from the alveolus and its crown has become 
worn, tiiat its fano-s are formed. These are at first 
hollow, and afterward filled, as v/ell as the cavity of 
the tooth, ])y the formation of new dentine. Erom 
this time tlie fangs cease to gro^v, but the tooth, con- 
stantly projected beyond the alveolar cavity, allows the 
walls which inclose it to contract; so that in extreme 
old age the sliaft, completely v/orn away, instead of the 
tooth, leaves several stumps formed by the fangs. 

"The replacement of the twelve molars is not at all 
like Vvdiat happens with the incisors. They grow im- 



KELATEVE SIZE OF THE GPvIINDERS. 71 

mediately below the temporary teeth, aud diNride their 
two fangs into four, the uhsorbing process continuing 
until the bodies are reduced to simple plates and fall 
off.'' 

In measuring the tceih in a large-sized head the 
following facts and figures were elicited: Length of 
grinder rows, 7 inches. Space between the sixth 
grinders, upper rows, measuring from the inner sur- 
faces, but not including the angles, 3 inches; center of 
rows, 2}f ; first grinders, not including the space of 
the angles, 2^. Lower rows: Between the sixth 
grinders, 2|-; center of rows, 1{-^; first grinders, 1-|-. 
Upper tush from first grinder, 2-J ; from third incisor, 
1^. Lower tush from grinder, 3-|; from incisor, |. 
Space between the upper tushes, 2 ; between the lower, 
If. Space between the upper corner incisors, measur- 
ing from center of teeth, 2; lower, 1||; between the 
upper dividers, II- ; lower. If. Distance around semi- 
circle of upper incisors, 4-fg-; around lower, 3|f. 

As a supplement to tlie above, the following extract 
is made from ''An Essay on the Teeth" by Surgeon 
John Hughes ("Veterinarian," 1841, "Proceedings 
Vet. Med. Ass.," p. 22) : 

" The upper and lower grinders will measure from 
2| to 3 inches in length. In transverse diameter the 
former exceed the latter in tlie proportion of 7 to 4. 
The aggregate measurement of the sockets of the up- 
per grinders is about 7 inches. The first tooth occu- 
pies one inch and a half of this space, the second 1|-, 
the tliirdl-i", the fourth 1, the fifth 1, and the sixth 1-J-. 
The breadth of the corresponding lowTr teeth is about 
the same as that of the upper." 



72 THE PERMAIs^EiTT DENTITION". 

There is a difference in the structure of all the teeth, 
and an expert can tell to which socket each belongs. 
They lit their sockets accurately/'^' are braced all round 
by the jawbone processes, and receive besides support 
and protection from the gums, which adhere to them 
tenaciously and are almost as hard as cartilage. Use 
and time, however, work changes, the teeth all wearing 
down, the incisors in particular changing shape and 
projecting outward. At the age of twelve years the 
gums begin to slacken, causing the teeth to look 
longer. The change from the upright position of the 
incisors, and the increased space between them and 
the canines, is caused by the elongation of the jaws, 
which carries the incisors outward. The canines do 
not change their position, but they become mere stubs. 

* " The manner of attachment of the human teeth is that 
termed ' gomphosis,' i. e., an attachment comparable to the fit- 
ting of a peg into a hole. The bony sockets, however, allow of 
a considerable degree of motion, as may be seen by examining 
the teeth in a dried skull, the fitting being in the fresh state 
completed by the interposition of the dense periosteum of the 
socket. This latter, by its elasticity, allows of a small degree 
of motion in the tooth, and so doubtless diminishes the shock 
which would be occasioned by m.astication were the teeth per- 
fectly immovable and without a yielding lining within their 
sockets." — C. S. Tomes, "Dental Anatomy" d-c, p. SS. 

John Hunter says (" Human Teeth ") : " The fangs of the 
teeth are fixed in the gum and alveolar processes by that species 
of articulation called goonphosis, which in some measure resem- 
bles a nail driven into a piece of wood. They are not, however, 
firmly united with the processes, for every tooth has some de- 
gree of motion; and in heads which have been boiled or macer- 
ated in water, so as to destroy the periosteum and adhesion of 
the teeth, we find them so loosely connected with their sockets 
that the incisors are ready to drop out, the grinders remaining, 
as it were, hooked, from the number and shape of their fangs/' 



THE HORSE AS A MILLER. 73 

Notwithstanding all these changes it is a rare thing to 
see a missing incisor or grinder. The canines, how- 
ever, owing perhaps to their sharp points, not only 
wear out, but now and then, in extreme old age, fall 
out. 

The permanent teeth agree with the temporary in 
but few respects, though the general appearance of the 
respective teeth is nearly the same. They differ in 
many respects. Their bodies are larger and denser, 
and their roots longer and stronger. The grooving of 
the incisors is the reverse ; the outer surface is usually 
double grooved, the inner smooth, both being slightly 
rounded. They are less upright in position, and less 
sharp, but are more discolored, and the "marks" (in- 
fundibula) are wider and deeper and wear out more 
slowly. They attain tlieir growth more slowly, and a 
healthy tooth continues to grow throughout life. 

In proof of the last assertion many authorities could 
be cited, but those that follow must suffice. It is a 
wise provision of Nature, as but for it a horse's teeth, 
particularly the grinders, would be worn to stubs in 
two or three years after tlieir development. Prof. 
M. H. Bouley and Surgeon P. B. Ferguson say (" Vet- 
erinarian," 18-14) : 

"The growth throughout life is a compensation for 
the enormous w^ear of the teeth, the liorse having to 
perform for himself that which the miller performs for 
man ; and thus during a very long time the teeth pre- 
serve, if not their form, at least their length." 

Prof. A. Chauveau, referring to the horse, says: 

" The permanent teeth present in their development 
a common but very remarkable characteristic, rarely 
4 



74 THE PEEMAI^EXT DEKTITIOI^. 

met with in other animals. Th^y are thrust up from 
the alveoh during the entire life of the animal to re- 
place the surface worn by friction ; so tliat the crown 
is formed successively by the various portions of the 
fang, each of which issues in its turn from the alveolar 
cavity." 

Prof. 0. S. Tomes says " the elevation of the tooth 
takes place quite independently of growth from a per- 
sistent pulp, and ni fact happens after the formation 
of its roots." 



CHAPTER IV. 

THE CANINE TEETH OR TUSHES. 

Practically Useless.— Different in their Nature from the other 
Teeth.— Were they formerly Weapons of Offense and De- 
fense?— Views of Messrs. Darwin, Himter, Bell, Youatt, and 
Winter.— Their time of Cutting the most Critical Period of 
the Horse's Life. 

The Canine Teeth {laniarii denies), comparatively 
speaking, are of little practical use; at least tliey are 
of little use to the modern horse. They have heeu 
much reduced in size during the evolution of the horse, 
and, if Mr. C, 11. Darwin's theory is correct, are prob- 
'al)ly "in the course of ultimate extinction." They 
distinguish the sex, it is true, but their loss would not 
be felt on that account. The horse sometimes uses 
them in tearing bark from trees, for he is by instinct 
his own (botanical) doctor, and the bark is his medi- 
cine. The sharp points of the tushes penetrate the 
bark more readily than the incisors, and apparently 
the horse wishes to save his incisors, thus showing his 
horse-sense. Their nature is different from that of 
the other teeth, for the incisors and grinders grow till 
old age. This is not the case Avith the tushes, and, 
farther, they are never in apposition (superposed), and 
consequent! V do not wear one another. 

The lower tushes, as before said, are about three- 
f^uirths of an inch from the corner incisors, and about 
three inches and a half from the first grinders. The 



76 THE CAKIJTE TEETH. 

space between the upper tushes and the corner incisors 
is doable that of the lower, and they are consequently 
three-fourths of an inch nearer the grinders. The dis- 
tances may vary a half an inch or more. The space 
between the tushes and grinders 2S> as already said, 
called the diastema. 

The average hight of the tushes when full grown is 
about three-fourths of an inch. They resemble tri- 
angles, having broad bases and sharp crowns, the latter 
being remarkable, says Prof. Owen, "for the folding in 
of the anterior and posterior margins of enamel, which 
here includes an extremely thin layer of dentine." 
They have a slight outward inclination, that of the 
lower teeth exceeding that of the upper. Their outer 
surface is oval, the inner (in the young horse) being 
deeply grooved. As age advances the inner snrfjxce 
becomes oval also, and the crowns more or less blunt. 
The root of a tush, which is longer than its body, 
has a distinct backward curvature, rendering the ex- 
traction of these teeth almost impossible. The tushes 
have no "marks" (infundibula), the nerve cavity ex- 
tending through nearly the entire length of the tooth. 

^Monsieur Lecoq says : 

"The free portion of the tusk, slightly curved and 
thrown oiitw^ard, particularly in the lower jaw, presents ^ 
two faces (internal and external), separated from one 
another by two sharp borders, which incline to the 
inner side, and meet in a point at the extremity of the 
tooth. The external face, slightly rounded, presents a 
series of fine striae, longitudinal and parallel. The 
internal has a conical eminence in its middle, whose 
point is directed toward that of the tooth, and is sep- 
arated from each border by a deep groove. 



SIMPLICITY OF THEIR STRUCTURE. 77 

" The fang of the tusk, more curved than the free 
j)ortioD, bears internally a cavity analogous to that of 
the root of the incisors, and, like it, diminishes in size 
and finally disappears as age advances ; but it is always 
relatively larger, because of the absence of the infun- 
dibulum in the canine teeth. 

" The structure of these teeth is much simpler than 
that of the incisors, consisting, as they do, of a central 
mass of dentine, hollowed by the pulp cavity, and cov- 
ered by an external layer of enamel, on which is de- 
posited a little cement." 

As there is more or less mystery about the tushes, 
and as they are important factors in the consideration 
of the problem of the evolution of the horse as well as 
other animals, a few extracts from the works of well- 
known scientific men, giving their views on the sub- 
ject, will i^rove interesting if not instructive. 

Mr. Charles R Darwin gives the following interest- 
ing account of tushes and their uses in certain animals, 
among them the horse (" Descent of Man," vol. ii, pp. 

245-6-7) : 

"Male quadrupeds which are furnished with tusks 
use them in various ways, as in the case of horns. 
The boar strikes laterally and upward, the musk-deer 
with serious effect downward. The walrus, though 
having a short neck and unwieldy body, ^can strike 
upward, downward, or sideways with equal dexterity.' 
The Indian elephant fights, as I was informed by the 
late Dr. Falconer, in a different manner according to 
the position and curvature of his tusks. When they 
are directed forward and upward, he is able to' fling a 
tiger to a great distance — it is said to even thirty feet; 



78 THE CANINE TEETH. 

when tliey are short and turned do^Tn^ard, he en- 
deavors suddenly to pin the tiger to the ground, and 
in consequence is daugerons to the rider, who is liable 
to be dismounted. 

'• Very few male quadrupeds possess weapons of two 
distinct kinds specially adapted for lighting with rival 
males. The male muntjac-deer {Cervulus), however, 
offers an exception, as he is provided with horns and 
exserted canine teeth. But one form of weapon has 
often been replaced in th.e course of ages by another 
form, as we may infer from wliat follows. With rumi- 
nants the development of horns generally stands in an 
inverse relation with that of even moderately Avell- 
developed canine teeth. Thus camels, guanacoes, 
chevrotains, and musk-deer are hornless, and they 
have efficient canines, these teeth being 'always of 
smaller size in the females than in the males.' Male 
deer and antelopes, on the other hand, possess horns, 
and they rarely have canine teeth, and these when 
present are always of smaller size, so that it is doubt- 
ful v/hether they are of anyseiwice in their battles. 
With Antelope montana they exist only as rudiments 
in the young male, disappearing as he grows old. 
Stallions have small canine teeth, but they do not 
appear to be used in fighting, for stallions bite v/ith 
their incisors, and do not open their mouths widely 
like camels and guanacoes. Whenever the adult male 
possesses canines now in an inefficient state, while the 
female has either none or mere rudiments, we may 
conclude that the early male progenitor of the species 
was provided with efficient canines, which had been 
partially transferred to the females. . The reduction of 
these teeth in the males seems to ha,ve followed from 
some change in their manner of fighting, often caused 



TUSHES TEJT FEET LON"G. 79 

(but not ill the case of the horse) by the development 
of new weapons." 

In the first volume of the "Descent of Man/' page 
139, Mr. Darwin attributes the reduction in size of the 
tushes in horses to their " habit of fighting with their 
incisor teeth and hoofs/' and on page 231, of the sec- 
ond volume, he continues the discussion of canines in 
different animals as follows: 

" In the male dugong the upper incisors form offen- 
sive weapons. In the male narwhal one of the upper 
teeth is developed into the well-known, spirally-twisted, 
so-called horn, which is sometimes from nine to ten 
feet long. It is believed that the males use these horns 
for fighting together, for ^an unbroken one can hardly 
be got, and occasionally one may be found with the 
point of another jammed into the broken place.' The 
tooth on the opposite side of the head in the male con- 
sists of a rudiment about ten inches in length, which 
is imbedded in the jaw. It is not, however, very un- 
common to find double-horned male narwhals in which 
both teeth are v/ell developed. In the females both 
teeth are rudimentary^ The male cach'alot* has a 

* " Spenn-wliale or cachalot {Physeter macrocephalus). My 
friend Mr. Broderip possesses a tootli of a male Physeter, with 
the base open and uncontracted, which measures nine inches 
and a half in length, nine inches in circumference, and weighs 
three ])Ounds. An ingenious whale-fisher has carved the chief 
incidents of his exciting and dangerous occupation on one side 
of this very fine tooth. The other side bears the following in- 
&cri])tion : ' The tooth of a sperm-whale, that was caught by the. 
ship Adam's crew, off Albemarle Point, and made 100 bbls. of oil, 
in the year 1817.' Below tlie inscription are two excellent 
figures of the cachalot, one spouting, the ot^her dead and marked 
for flensing."— Ow;e;i'5 "Odontography," Vol. /, pp. 353-4- 



80 THE ca:n'I]s-e teeth. 

Lirger head than the female, and it no doubt aids these 
animals in their aquatic battles. Lastly, the adult 
male ornithorhyn'chus is provided with a remarkable 
apparatus, namely, a spur on the foreleg, closely re- 
sembling the poison fang of a venomous snake. Its 
use is not known, but we may suspect it serves as a 
weapon of offense. It is represented by a mere rudi- 
ment in the female." * 

The foregoing extracts would not be complete with- 
out giving the viev»^s of this great disciple of evolution 
concerning the same teeth in man. He says (" Descent 
of Man," voL i, p. 198) : 

"We have thus far endeavored rudely to trace the 
genealogy of the vertebrata by the aid of their mutual 
affinities. We will now look to man as he exists, and 
we shall, I think, be able partially to restore during 
successive periods, but not in due order of time, the 
structure of our early progenitors. This can be effected 
by means of the rudiments which man still retains, by 
the characters which occasionally make their appear- 
ance in him through reversion,! and by tiie aid of the 
principles of morphology and embryology.| The early 

* For further information concerning this strange animal see 
tlie " Vocabulary." 

f " The occasional appearance at the present day of canine 
teeth which project above the others, with traces of a diastema 
or open space for the reception of the opposite canines, is in all 
probability a case of reversion to a former state, when the pro- 
genitors of man were provided with these weapons." — "Descent 
of Man," Vol. II, p. SOD. 

\ " The human em'bryo re&ombles in various points of struc- 
ture certain low forms when adult. For instance, the heart at 
first exists as a simple pulsating* vessel ; the excreta are voided 
through a cloacal passage, and the os coccyx projects like a true 



THE EARLY PROGrXITORS OF MAN". 81 

progenitors of man were no doubt once covered with 
hair, both sexes having beards. Their ears were 
pointed and capable of movement, and their bodies 
were provided with a tail, having tlie proper muscles. 
Their limbs and bodies were also acted on by muscles 
which now only occasionally reappear, but are normally 
present in the quadrumana. ^The great artery and 



tail, 'extending considerably beyond the rudimentary legs.* 
The great-toe, as Prof. Owen remarks, 'which forms the ful- 
crum when standing or walking, is perhaps the most character- 
istic peculiarity in the human structure ;' but in an embryo 
about an inch in length, Prof. Wyman found that the great-toe 
was shorter than the others, and instead of being parallel to 
them, • projected at an angle from the side of the foot, thus cor- 
responding with the permanent condition of this part in the 
quadrumana.' * * * When the extremities are developed, 
* the feet of lizards and mammals, the wings and feet of birds, 
no less than the hands and feet of man, all arise from the same 
fundamental form.' (Von Baer)." — "Descent of Man," Vol. I, pp. 
U-IG. 

"Each human individual is developed from an egg, and this 
egg is a simple cell, like that of any animal or plant. The em- 
bryo, in the early stages of development, is not at all different 
from those of ether animals. At a certain period it has essen- 
tially the anatomical structure of a lancelet (the lowest verte- 
brate), later of a fish, and in subsequent stages those of am- 
phibian and mammal forms. In the further evolution of these 
mammal forms, those first appear which stand lowest in the 
series, namely, forms allied to beaked animals (ornithorhyn- 
chus) ; then those allied to pouched animals (marsupials), which 
are followed by forms most resembling apes, till at last the 
peculiar human form is produced as the final result. Every one 
knows that the butterfly proceeds frpra a pupa, the pupa from a 
caterpillar, to which it bears no resemblance, and again the cat- 
erpillar from the e^g of the butterfly. But few, except those of 
the medical profession, are aware that man, in the course of his 
individual evolutiou, passes through a series of transformations 



82 THE CAKIKE TEETH. 

nerve of the humerus ran through a supra-condyloid 
fora'men. At this or some earlier period the intestine 
gave forth a much larger diverticulum or csecum than 
that now existing. The foot, judging from the con- 
dition of the great-toe in the fetus, was then prehen- 
sile, and our early progenitors were no douht arboreal 
in their habits, frequenting some warm, forest-clad 
land. The males were*" provided with great canine 
teeth, which served them as formidable weapons."* 

no less astonishing and remarkable than the xvell known meta- 
morphoses of the butterfly. * * * An examination of the 
human embryo in the third or fourth week of its evolution 
shows it to be ahogether different from the fally developed 
man, and that it exactly corresponds to the undeveloped em- 
bryo-form presented by the ape, the dog, the rabbit, the horse, 
and other mammals, at the same stage of their ontog'eny (germ 
history), which may be demonstrated by placing the respective 
embryos side by side. At this stage it is a bean-shaped body of 
very simple structure, with a tail behind, and two pairs of pad- 
dles, resembling the fins of fish, and totally dissimilar at the 
sides to the limbs of man and other mammals. Nearly the 
whole of the front half of the body consists of a shapeless head, 
without a face, on the sides of which are seen gilh fissures and 
gill-arches, as in fishes. •» * * The human embryo j)asses 
through a stage in which it possesses no head, no brain, no 
skull ; in which the trunk is still entirely simple and undivided 
into head, neck, breast, and abdomen, and in which there is no 
trace of arms or legs," — Ernst Heinrich Haeckel, "The Ewlution 
of Man,'' Vol. I, pp. 3, IS, 258. 

* Mr. Darwin continues : " At a much earlier time the uterus 
was double ; the excreta were voided through a cloaca, and the 
eye was protected by a third eyelid or nictitating membrane. 
At a still earlier period the progenitors of man must have been 
aquatic in their habits, for morphology plainly tolls us that our 
lungs consist of a modified swim-bladder, which once served as 
a float. The clefts on the neck in the embryo of man show 
where the branchiae once existed," &c., &c. 



DAKWIX OJTLY CORROBORATES HUNTER. 83 

Again, on page 138 of the same volume, Mr. Darwin 

says : 

"The early progenitors of man were, as previously 
stated, probably furnished with great canine teeth ; but 
as they gradually acquired the habit of using stones, 
clubs, or other weapons for fighting with their enemies, 
they would have used their jaws and teeth less and 
less. In this case the jaws and the teeth would have 
become reduced in size, as we may feel sure from nu- 
merous analogous cases."* 

Dr. John Hunter, writing nearly one hundred years 
before Mr. Darwin's time, says ('' The Human Teeth," 
p. 29) : 

" The use of the cuspidati would seem to be to lay 
hold of substanceSj perhaps even living animals. They 
are not formed for dividing, as tlie incisors are, nor 
are they fit for grinding. We may trace in these teeth 
a similarity in shape, situation, and use, from the most 
imperfectly carnivorous animal — which we believe to 
be the human species — to the most perfectly carnivo- 
rous, namely, the lion." 

The editor of Dr. Hunter's work, Mr. Thomas Bell, 
F.R.S., comments as follows on the above extract: 

" That our conclusions as to the functions of an 
organ as it exists in man, when drawn exclusively from 
analogous structures in the lower animals, will fre- 

* "The jaws, toijether with their muscles, would then have 
become reduced throiinrh disuse, as would the teeth, throujih the 
not well understood principles of correlation and the economy of 
growth ; for we everywhere see that parts which are no longer 
of service are reduced in size." — "Descent of Man.'" 



84 The CANIinE TJEETH. 

quentlyprove erroneous, is strikingly shown in these 
observations on the use of the cuspidatus. The simple 
and obvious use of this tooth, in the human species, is 
to tear such portions of food as are too hard or tough 
to be divided by tlie incisors ; and we frequently find 
it far more developed in animals which are known to 
be exclusively frugivorous. Not only is its structure 
wholly unadapted for such an object as that assigned 
to it in the text, but there is no analogous or other 
ground for supposing that man was originally con- 
structed for the pursuit and capture of living prey. 
His naturally erect position and the structure of the 
mouth would render this impossible by the means in- 
ferred by Hunter; and the possession of so perfect an 
instrument as the hand obviates the necessity of his 
ever employing any other organ for the purpose of 
seizing or holding food of whatever description." 

Prof. William Youatt says ("The Horse," p. 22G): 

"At the age now under consideration (the fourth 
year) the tushes are almost peculiar to the horse, and 
castration does not appear to prevent or retard their 
development. All mares, however, have the germs of 
them ill the chambers of the jaws, and they appear 
externally in the majority of old mares. Their use is 
not evident. Perhaps in the wild state of the horse 
they are weapons of offense, and he is enabled by 
them to more firmly seize and more deeply wound his 
enemy." * 

" Prof. C. S. Tomes says : " In the domestic races the tiisks of 
boars are much smaller than in the wild animal, and it is a curi- 
ous fact that in domestic races which have become wild, the 
tusks increase in size at the same time that the bristles become 
more pronounced. Mr. Darwin suggests that the renewed 



THEIR PHYSIOLOGICAL RELATIONS. 85 

Surgeon J. H. Winter, the author of a work entitled 
" On the Horse," says : 

'' It is difficult to assign their use. Their position 
precludes the possibility of their being used as weapons 
of offense or defense. They may be viewed as a link 
of uniformity so commonly traced in the animated 
world." 

Prof. William Percivall says that the cutting of the 
tushes causes the constitution more derangement than 
all the other teeth, and Prof. Youatt and other high 
authorities entertain similar views. The present chap- 
ter, therefore, is a proper one in which to discuss " the 
effects of dentition on the system generally." The 
discussion of the subject is left to well-known men. 
Messrs. Youatt and Percivall were many years ago the 
editors of "The Veterinarian," but their books are 
probably the best monuments to their memory. Prof. 
William Williams is the President of the Edinburgh 
Veterinary College. Prof. Youatt says (" Tiie Horse," 
p. 230) : 

" This is the proper place to speak of the effect of 
dentition on the system generally. Horsemen in gen- 
eral think too lightly of it, and they scarcely dream of 
the animal suffering to any considerable degree, or 

growth of the teeth may perhaps be accounted for on the prin- 
ciple of correlation of growth, external agencies acting on the 
skin, and so indirectly influencing the teeth." 

A strictly analogous result might or might not follow in the 
case of the horse. If so, the tushes would probably be used as 
weapons of offonse and defense. It is reasonable to suppose that 
they were so used by the early progenitors of the horse, whose 
large tushes are described in the succeeding chapter by Prof. 
Marsh. 



80 THE CAKIN'E TEETH. 

absolute illness being produced. Yet he who has to 
do with young horses will occasionally discover a con- 
siderable degree of febrile affection Avhich he can refer 
to this cause alone. Fever, cough^ catarrhal and cuta- 
neous affections, diseases of the eyes, diarrhea, dysen- 
tery, loss of appetite, and general derangement will 
frequently be traced to irritation from teething. It is 
a rule scarcely admitting of the slightest deviation, 
that, when young horses are laboring under febrile 
affection, the mouth should be examined, and if the 
tushes are prominent and pushing against the gums, a 
crucial incision should be made over them."* 

Prof. Percivall says (*• Hippopathology," vol. ii, p. 
225) : 

"There was a time when I treated the subject of 
dentition so lightly as to think that horses never suf- 
fered from such a cause. Experience, however, has 
altered my opinion. I now frequently discover young 
horses with disorders or febrile irritations the produc- 
tion of which I hesitate not to ascribe to teething. 
Many years ago I was consulted concerning a horse 
which had fed sparingly for a fortnight and lost rap- 
idly in condition. His owner, a veterinary surgeon, 
was apprehensive about his life. Another surgeon was 
of opinion that the ^cudding' arose from preternatural 

*^ Prof. Youatt's real sentiments are doubtless here expressed, 
but, unfortunately for bis consistency, on page 227 of tbe same 
work, in speakina; of tbe deran£:;eraent caused by teetbing in 
cbildren and dogs, be says : " Tbe borse appears to feel little 
inconvenience. The gums and palate are occasionally some- 
wbat bot and swollen, but tbe sli^btost scarification will remove 
tbis." Perbaps Prof. Youatt, like Prof. Percivall, cbaufred bis 
opinion late in life, and neglected to remove tbe blemisb from 
bis book. 



WHAT CHAiTaED PROF. PERCIVALL'S MIIiTD. 87 

bluntness of the molar teetli, which were filed. It 
was after this that I saw the horse, and I must confess 
I was ut first quite as much at a loss to offer a satisfac- 
tory interpretation of the case as others had been. 
While meditating, however, after my inspection of the 
horse, on the apparently extraordinary nature of the 
case, it struck me that I had not seen the tushes. I 
went back into the stable and discovered two little 
tumors, red and hard, in the situation of the inferior 
tusks, which, when pressed, gave the animal insuffer- 
able pain. I instantly took out my pocket-knife and 
made crucial incisions through them both, from which 
moment the horse recovered his appetite, and by de- 
grees his wonted condition. This case was the turn- 
ing point in my practice, and caused me to look more 
closely into dentition. 

*^The cutting of the tushes, which may be likened 
to the eye-teeth of children, costs the constitution 
more derangement than all the other teeth put to- 
gether; on which account, no doubt, it is that the 
period from the fourth to the fifth year proves so crit- 
ical to the horse. Any disease, pulmonary in particu- 
lar, setting in at this period, is doubly dangerous. In 
fact, teething is one cause of the fatality among young 
horses at this period. 

*^ D'Arboval tells us to observe how the vital energy , 
becomes augmented about the head, and upon the 
mucous surfaces in particular. He says: *A local 
fever originates in the alveolar cavities. The gums 
become stretched from the pressure of the teeth against 
them. They dilate, sometimes split, and are red, hot, 
and painful. The roots compress the dental nerves 
and irritate the periosteal linings of the alveolar cavi- 
ties. These causes will enable us to explain many 



88 THE CANIKE TEETH. 

morbid phenomena in horses about this, the most crit- 
ical period of their lives.' 

"When young Jiorses are brought to me now for 
treatment/' continues Prof. Percivall, "I invariably 
examine tlie teeth. Should the tiisks be pushing 
against the gums, I let them through by incisions 
over their summits, and I extract any of the tempo- 
rary teeth that appear to be obstructing the growth of 
the permanent. In this way I feel assured I have seen 
catarrhal and bronchial inflammations abated, coughs 
relieved, lymphatic and other glandular tumors about 
the head reduced, cutaneous eruptions got rid of, de- 
ranged bowels and urinary organs restored, appetite 
returned, and lost condition repaired. 

"I am quite sure too little attention has been paid 
to the teeth in the treatment of young horses, and I 
would counsel those who have such charges by no 
means to disregard this remark, trifling as it may 
appear. The pathognomonic symptoms calling our 
attention, whether in young or old horses, if not to 
the teeth themselves, to the mouth in general, are 
large discharges of saliva from the mouth, with occa- 
sional slobbering; cudding of the food; difficulty of 
mastication or deglutition, or both, and stench of buc- 
cal secretion, perhaps of the breath as well." 

Prof. Percivall continues the discussion of the sub- 
ject of dentition and its effect on the health of the 
horse, dwelling more particularly on the disorder 
known as lampas. He says: 

"There is connected with dentition another pecu- 
liarity in the horse which we must not allow to pass 
unnoticed. Although the period of teething, properly 



LAMP.iS CAUSED BY TEETHING. 



89 



speaking, may be said to terminate at the fifdi year, 
yet we must recollect it has been satisfactorily demon- 
strated that there is a process of growth going on in 
the teeth throughout the remainder of life ; so that m 
fact, at no period may the animal be said to be free 
from the influence of dentition. This accounts for 
lampas occurring in old as well as young horses, and 
furnishes mv mind with strong proof that the tumidity 
of the bars "of the mouth is dependent on operations 
goino- on in the teeth, and on that cause alone. ^ 

" What we nowadays understand by lampas is an 
unnatural prominence or tumidity of the cartilaginous 
bars forming the roof of the mouth, ^^^^^urally, the 
bars are pale-colored, whereas in a mouth affected with 
lampas they become red and tumid, losing their cir- 
cumflecture, and swelling to a level with the crowns of 
the incisor teeth, and in some cases even beyond them. 
This apparent augmentation of substance is ascnbable 
to congestion of blood-vessels, but not to that alone. 
I believe that in many cases there will be found to be 
some serous and albuminous infiltration into the cel- 
lular membrane at! aching the bars to the hard palate, 
and that this will account for the length of time the 
swelling sometimes continues, as well as for the httle 
relief, in regard to their diminution, which in such 
cases attends lancing of the gums. 

" Although in young horses it is, I believe, admitted 
that lampas is caused by the cutting of the teeth, yet 
in old horses there are those who asci;ibe its produc- 
tion to other causes, and imagine it has a great deal to 
do with a horse's health, or rather with his fceduig. 
That lamnas may in some cases be the cause of tender- 
ness in mastication, 1 do not deny; but, at the same 
time, I think I may safely ullirm that in nine cases out 



^ 



90 THE CANII^E TEETH. 

of ten the cause of loss of appetite will be found else- 
where. The reason why lampas appears in aged horses 
is, in my opinion, as before stated, on account of the 
continuance of the process of growth in the teeth 
throughout life, with the nature and law^s of which we 
are, in our present state oi knowledge, too little ac- 
quainted to pretend to say why it should exist in one 
horse and not in another, or why it should only at 
times appear in the same horse. 

*''ls lampas a disease? Tlie complaints which daily 
reach our ears persuade us it is. Every groom having 
an unthriving horse, or one that docs not feed, is sure 
to search for lampas. If he finds it, in his mind the 
cause of lack of thrift is detected, and the remedy 
obvious — burning- Many a horse has been subjected 
to this torturing operation, and has thereby got added 
to his other ailment-s a foul, sloughy, carious sore on 
the roof of his mouth. 

" Supposing that lampas be owing to the teeth, do 
not the teeth require removal, and not the bars of the 
mouth? In cutting or burning away lampas we mis- 
take the effect for the cause. If lampas is not produced 
by the irritation of teething, then I would like to be 
informed what does cause it." 

Prof. Youatt says of lampas (" The Horse," p. 219) : 

^' It may arise from inflammation of the gums, 
propagated to the bars when the colt is shedding his 
teeth — young horses being more subject to it than 
others — or from some febrile tendency in the consti- 
tution generally, as when a J^oung horse has lately 
been taken from grass, and has been over-fed or insuf- 
ficiently exercised. It is well to examine the grinders, 



MASHES xVND LANCIKG RECOMMENDED. 91 

and more particularly the tuslies, in order to ascertain 
whether they are making their way through the gums. 
If so, incisions should be made across the swollen 
gums, and immediate relief will follow. At times it 
appears in aged horses, the process of growth in the 
teeth of the horse continuing during life. 

^•The brutal custom of farriers, who sear and burn 
the bars with a red hot iron, is most objectionable. It 
is torturing the horse to no purpose, and may do seri- 
ous injury. In a majority of cases the swelling will 
subside without medical treatment. A few mashes 
and gentle alteratives will give relief, but sometimes 
slight incisions across the bars with a lancet or pen- 
knife may be necessary. Indeed, scarification of the 
bars in lampas will seldom do harm, though it is not 
as necessary as is generally supposed." 

Concerning "Diseases occurring during Dentition" 
Prof. William Williams says (" Principles and Practice 
of Veterinary Surgery," p. 476) : 

"In the horse the temporary grinders are replaced 
by permanent ones when he is from three to four years 
old, and in the ox at from two years and six months 
to two years and nine months. In cattle the cutting 
of the permanent molars is occasionally a matter of 
some difficulty owing to the unshed crowns of the 
temporary teeth becoming entangled with the new 
teeth, and thus proving a source of irritation and pre- 
venting the animal from feeding. In some parts of 
the country such animals are called 'rotten,' from their 
emaciated condition, and perhaps from the fetor ema- 
nating from the mouth. When cattle of this age stop 
feeding, lose condition, or drivel from the mouth, the 



92 THE CAXIKE TEETH. 

teeth should be examined, and if the unshed molars 
are causing irritation, they should be removed with 
the forceps. Hundreds of young cattle have been sac- 
rificed from this cause — actually dying of starvation. 
In the horse tlie same condition of the grinders may 
exist, but it is very unusual. The corner incisors, 
however, may present the same anomalous condition. 
Horses from four years to four years and six months 
old should have their teeth examined occasionally to 
see if all is going on well. 

'• Horses at four years old are subject to a distressing 
cough. At this age the third temporary grinder is 
replaced by its permanent successor, and at the same 
time the sixth grinder is being cut. Some irritation 
exists in the gums during the eruption of all the teeth, 
and in some instances it is excessive, extending from 
the gums to the fauces and larynx. This is particu- 
larly the case with the sixth grinder, and as a result of 
the extension of the irritation, cough is excited, usually 
in the morning, when the animal begins to feed. It 
is loud, sonorous, and prolonged, the horse frequently 
coughing twenty, thirty, or even forty times without 
ceasing. It is a throat cough, originating in laryngeal 
irritation. 

" The treatment for this, which may be truly said to 
be a tootli-cough, is careful dieting on crushed food; 
hay, not much bran ; grass, if in season, or roots if 
grass is not obtainable ; alkaline medicines, more par- 
ticularly the bicarbonate of soda; gentle aperients 
occasionally, if the bowels be irregular. If the faeces 
are fetid the fetor will be much diminished by a few 
doses of the hyposulj^hite of soda, the mouth to be gar- 
gled with some cooling mixture, such as the borate of 
soda or alum." 



DEisTITION FEYEE. 93 

Of "Dentition Fever" Prof. Williams says ("Prin- 
ciples and Practice of Veterinary Surgery," p. 479) : 

" Horses from three to four years old are more sub- 
ject to this species of dental irritation than those of a 
more tender age, and it is well known among horsemen 
that they will stand more fatigue at a more tender age 
than they will at this. The reason is because teething 
is now at the hight of its activity. When the animal 
is three years old, eight permanent grinders are being 
cut, and four permanent incisors are in active growth 
within the jaws. At four years of age the same num- 
ber of grinders are out, and the same number of inci- 
sors are at a more advanced stage of growth within the 
jaws, in addition to the canme teeth, which make 
their appearance about this time. 

" No wonder then that the eruption of so many teeth 
is a source of irritation and fever. The best treatment 
is to throw the animal off woi'k, turn him to grass if 
the weather permits, or into a loose box in a well ven- 
tilated spot, and give him rest until the process of den- 
tition is completed. If the gums are red and swollen, 
lancing them will prove a source of great relief." 

On page 503 Prof. Williams, in speaking of crib- 
biting and wind-sucking, says: "Want of work and 
the irritation of teething are generally the causes of 
these vices." 



CHAPTEE V. 

THE EEMiS'AIs'T TEETH. 

Usually regarded as Plienomenons. — The Name. — Traced to 
tlie Fossil Horses, in wliicli (in tlie Pliocene Period) they 
"Ceased to be Functionally Developed." — Nature's Meta- 
morphoses. — " The Agencies which are at work in Modeling 
Animal and Vegetable Forms." — Why Remnant Teeth are 
often, as it were, Prematurely Lost, — Fossil Horses and a 
so-called Fossil Man. 

The Eemnant or "so-called wolf-teeth" are one of 
the most interesting features of the horse's dental sys- 
tem. They are generally regarded as phenomenons, 
. hut their line of descent is as direct as that of the first 
premolars (grinders), which have, as it were, almost 
absorbed them, and have increased in bulk nearly in 
proportion to the decrease in bulk of the Eemnant 
teeth. 

As the word "wolf" is another name for that which 
is hurtful or destructive, and as these teeth as well as 
supernumerary teeth, with which, however, they should 
never be confounded, sometmies do injury, the generic 
name, " wolf- teeth," is not a bad one. But, since these 
piirticular teeth are hereditary, being beyond doubt the 
remains of teeth that were once functionally developed, 
they require a specific name ; I have therefore adopted 
the name EsMifAisT Teeth. 



PROF, marsh's researches. 95 

In the evolution of the horse from an animal of 
about the size of a fox to his present proportions, it is 
not strange that radical physical changes, of the teeth 
as well as other organs, should have occurred, or that 
they are in harmony with Ins bodily requirements as 
well as his usefulness to man. Small, four-toed limbs 
would support the body of an animal no larger than a 
fox or a sheep, but they would require additional size 
and strength to support the small horse (Hipparion) 
of the Pliocene period, or the large horse of the present 
period (Equus). This additional strength was gradu- 
ally acquired by the enlargement of the limbs and the 
solidification, as it were, of four toes into one, it being 
as natural, in conformity to the law of adaptation, for 
a line of succeeding animal forms to undergo bodily 
changes as for an individual form to do so. 

During these metamorphoses equally A-aried and 
interesting changes occurred in the horse's dental sys- 
tem, which are described by Prof. 0. C. Marsh, of Yale 
College, in the article "Horse, Fossil," in "Johnson's 
Xew Universal Cyclopedia (vol. ii, p. 906). He gives a 
general description of the changes that have occurred 
in species of three geological periods, namely, the 
Phocene, Miocene, and Eocene, those of the two last 
named having forty-four functionally developed teeth. 
The part of the article which refers to the teeth is as 
follows : 

"In the Pliocene tertiary period the horse was rep- 
resented by several extinct genera, the best known be- t 
ing Hipparion (or Hippotherium). The species are 
small, as the n:ime im])lies, Hipparion being a dimin- 
utive from the Greek hippos, a ^ horse.' In tlie ui)per 
molar teeth there is in Hipparion, on the anterior por- 



96 THE REMI^AKT TEETH. 

tion of the inner side, an isolated ellipse of enamel 
inclosing dentine, and not joined with the main body 
of the tootii by an istlimus of dentine, as in Equus, at 
least until the teeth are nearly worn out. Anchippns, 
also from tlie Pliocene, resembled in its teeth Anchi- 
therium of the Miocene, a genus now considered as 
typical of a family distinct from that of the horse. In 
Anchitherium the molars have short crowns, devoid of 
cement, and are inscribed by distinct fangs. The Mio- 
cene species were not larger than a sheep. The Eocene 
representatives of the group were still smaller, the 
largest hardly exceeding a fox in size. They belong 
to the genus Orohippus. The dentition is very simi- 
lar to that of Anchitherium, but the first upper pre- 
molar is larger and tlie succeeding ones smaller than 
in that genus. The diastema, or 'place for the bit,' is 
distinct. The canines are large, and near the incisors. 
The crowns of the molars are short and jdestitute of 
cement, and the skeleton is decidedly equina in its 
general features. 

"The gradual elongation of the head and neck may 
be said to have already begun in Orohippus, if we 
compare that form with other most nearly allied mam- 
mals. The diastema was well developed even then, but 
increased materially in succeeding genera. The num- 
ber of teeth remained the same until the Pliocene, 
when the front lower prenwiar was lost, and suljse- 
quently the corresponding upper tooth ceased to he func- 
tionally developed.'-' The next upper premolar, which 
in Orohippus was the smallest of the six posterior 



* The italics are mine. This " corresponding npper tooth 
that ceased to be functionally developed," is the identical tootli 
that now appears as a mere remnant. 



THE LARGE TUSHES OF OROHIPPUS. 97 

teeth, rapidly increased in size, and finally became the 
largest of the series. The grinding teeth had at first 
very siiort crowns, without cement, and were inserted 
by distinct roots. In Pliocene species the molars be- 
came longer, and were more or less coated with cement. 
The modern horse has very long grinders, without 
true roots, which are covered witi* a thick external 
layer of cement Tl»e large canines of Orohippus be- 
came gradually reduced in the later genera, and the 
characteristic 'mark' upon the incisors is found only 
in tlie later forms. It is an interesting fact that the 
peculiarly equine features acquired by Orohippus are 
retained persistently throughout the entire series of 
succeeding forms." * 

* " The raicient Orohippus had all four digits of the fore-feet 
well developed. In Mesohippus, of the nest period, the fifth 
toe is only represented by a rudiment, and the limb is supported 
by the second, third, and fourth, the middle one being the 
largest. Hipparion of the Later Tertiary still has three digits, 
but the third is much stouter, and the outer toes have ceased to 
be of use, as they do not touch the ground. In Equus the lat- 
eral hoofs are gone, and the digits themselves are represented 
only by the rudimentary splint-bones. The middle or third 
digit supports the limb, and its size has increased accordingly. 
The corresponding changes in the posterior limb of these genera 
are very similar but not so striking, as the oldest type (Orohip- 
pus) had but three toes behind. The earlier ancestor of the 
^roup, perhaps in the lowest Eocene, probably had four on this 
foot and five in front. Such a predecessor is as clearly indicated 
by the feet of Orohippus as the latter is by its Miocene relative. 
A still older ancestor, possibly in the Cretaceous, doubtless had 
five toes on each foot, the typical number in mammals. This 
reduction in the number of toes may perhaps have been due to 
elevation of the region inhabited, which gradually led the ani- 
mals to live on higher ground, instead of the soft lowlands, 
Avhero a many-toed foot would bo most "useful." — Frof. 0. C. 
Marsh. 

5 



98 THE rem:n'A]s^t teeth. 

The article closes as follows: 

"Such is, in brief, a general outline of the more 
marked changes that appear to have produced in 
America the highly specialized modern Equus from 
its diminutive, four-toed predecessor^ the Eocene Oro- 
hippus. The line of descent appears to have been 
direct, and the remains now known supply every im- 
portant intermediate form. Considering the remark- 
able development of the group throughout the entire 
tertiary period, and its existence even later, it seems 
very strange that none of the species should have sur- 
vived, and that we are indebted for our present horse 
to the Old World."* 

* The following extracts from Prof. C. S. Tomes's " Dental 
Anatomy, Human and Comparative" (pp. 247-8, 2'54-5), explain 
some of the causes of the metamorphoses described by Prof. 
Marsh : " He would indeed be a rash man who ventured to as- 
sert that we had recognized all the agencies wjiich are at work 
in the modeling of animal and vegetable forms ; but it is safe to 
say that, at the present time, we are acquainted with several 
agencies which are in constant operation, and which are com- 
petent to profoundly modify animals in successive generations. 
We know of 'natural selection,' or 'survival of the fittest,' an 
agency by which variations beneficial to their possessors will be 
preserved and intensified in successive generations; of 'sexual 
selection,' which operates principally by enabling those pos- 
sessed of certain characters to propagate their race, while others 
less favored do not get the opportunity of so doing; of 'con- 
comitant variation' between different parts of the body, an 
agency much more recondite in its operations, but by which 
agencies affecting one part may secondarily bring about altera- 
tions in some other part. 

" The doctrine of natural selection, or survival of the fittest, 
is as applicable to the teeth of an animal as to any part of its 
organization, and the operation of this natural law will be con- 
stantly tending to produce advantages or 'adaptive' differences. 
On the other hand, the strong power of inheritance is tending to 



NOT TtARE, BUT EASILY LOST. 99 

Remnant teeth are not rare, but it is rare for them 
to persist in the jaws till even middle age. However, 

preserve even that which, in the altering conditions of life, has 
become of very li ule us \ Tiius we may understand rudimentary 
teeth to be teeth which are in process of disappearance, having 
ceased to be useful to their possessors, hut still for a time, 
through the influence of inheritance, lingering upon the scene. 
Some teeth have disappeared utterly. Thus the upper incisors 
of ruminants are gone, and no rudiments exist at any stage ; 
others still remain in a stunted form, and do not persist through- 
out the lifetime of the animal, as, for instance, the first premo- 
lars of the horse, or two out of the four premolars of most bears. 

" Teeth are profoundly susceptible of modification, but amid 
all their varied forms, the evidences of descent from ancestors 
whose teeth departed less from the typical mammalian dentition 
are clearly traceable by the existence of rudimentary teeth and 
other such characters. * * * The power of inheritance is 
constantly asserting itself by the retention, for a time at least, 
of parts which have become useless, and by the occasional reap- 
pearance of characters which have been lost. •- * * Things 
that are rudimentary ofren teach us most ; for being of no pres- 
ent use, they are not undergoing that rapid change in adaptation 
to the animal's habits which may be going on in organs that 
are actively employed." 

Horses are not the only animals that have had or are having 
changes in their dentition. Mr. C. R. Darwin says ("Descent of 
Man," vol. i, p. 25): "It appears as if the posterior molar or 
vv'isdom-teeth were tending to become rudimentary in the more 
civilized races of men. They are rather smaller than the other 
teeth. In the Melanian races, on the other hand, the wisdom- 
teeth are usually furnished with three separate fangs, are gen- 
erally sound, and differ in size from the other molars less than 
in the Caucasian races. Prof. SchaafFhausen accounts for this 
difference between the races by 'the posterior dental portion of 
the jaw being always shortened ' in those that are civilized, and 
this sliortening may, I presume, be safelv attributed to civilized 
men habitually feeding on soft, cooked food, and thus using 
their jaws less. I am informed by Mr. Brnce that it is becoming 
quite a common practice in the United States to remove some 




100 THE KEMNAKT TEETH. 

there may be cases where they never appear; but it 
by no means follows that because a horse is not in pos- 
session of them that he never had any. There are 
various causes for their frequent absence, but the chief 
cause is their small size. Remnant 
teeth of the lower jaw, wliich are 
very rare, are probably cases of ^' re- 
version to a former state." * If these 
latter teeth were not expelled in the j.^^,,^,, ,^^,^ . ^^^.^^^ 
manner explained below by Mons. si^.e.-oric,inai. 

Lecoq, the probability is that they would not long- 
withstand the friction of the bit. The upper teeth, 
liowever, while they may sometimes be expelled by the 
bit, are comparatively little disturbed by i^, which 
probably accounts for their now and then remaining 
in the jaws for years. Another reason for their per- 
sistence is that their roots are long in proportion to 
their bodies. The reason why these teeth should not 
be confounded with supernumerary or abnormal teeth 
will appear in the succeeding chapter, which is devoted 
to the consideration of the latter. 

Monsieur Lecoq gives cogent reasons for the fre- 
quent absence of Remnant teeth. He says: 

" Supplementary molars are sometimes met with in 
front of the true ones, and there may be four of them, 
two in either jaw, above and below. They are small 
teeth, having but little recemblance to the others, are 
frequently shed with the first deciduous molar, and 
are not replaced. The first rephicing (permanent) 
molar is always a little more elongated than that 

of the molar teetli of cliildren, as tlie jaw does not grow large 
eDough for tlie perfect development of the normal number." 
♦ See the second reference note, page 80. 



HOW THEY MAY BE LOST. 101 

Vv'hich it succeeds, and it frequently expels at the same 
time tlie supplementary molar; so that if forty-four 
teeth be developed in the male horse, it is very rare 
that they are all present at the same time." 

That Eemnant teeth are usually regarded as phe- 
nomenons is abundantly proved by some of the ex- 
tracts that follow. In ''Johnson's New Universal 
Cyclopedia" (p. 995), article "Horse," it is said: 

"An additional small tooth is occasionally found in 
advance of the upper molar series. This tooth, when 
present, is the smallest of all the teeth, and, as it has 
neither predecessor nor successor, its nature is in 
doubt." 

As the nature of these teeth appeared to be clearly 
explained in the article "Horse, Fossil," which imme- 
diately follows that on the " Horse," I wrote to Prof. 
Joseph Lejdy, telling him I believed the "wolf-teeth" 
were the remnants of the teeth that "ceased to be 
functionally developed," and asked his opinion about 
the matter. Writing under date of "Philadelphia, 
Nov. 26, 1878," he said: 

* -- * "I think you are right in supposing that 
the little premolars referred to by Prof. Marsh as the 
* corresponding upper teeth,' which * ceased to be func- 
tionally developed,' are the so-called 'w^olf-teeth.'" 

Another letter, addressed to Prof. Theodore Gill, 
elicited the following reply, which was dated "Smith- 
sonian Institution, Washington, D. C, Nov. 25, 18T8:" 

* * '•'' "The complete dentition of the adult 
horse is represented by the formula: I., f ; C, i; 
D., -}-; P. M., I; M., |x2 = 12. The ^ small wolf or 



102 THE REMNAKT TEETH. 

supernumerary tooth that appears in front of the first 
upper premolar/ is the more or less persistent first 
deciduous molar (d 1) of the first series, which is not 
succeeded by a first premolar. The premolars are con- 
sequently P. M., 2, 3, and 4 of the typical educabilian 
dentition.^' 

Prof. Richard Owen, who, like Drs. Gill and Leidy, 
has a clear conception of the subject, says : 

" The second incisor appears between the twentieth 
and fortieth days, and about this time the first small, 
deciduous premolar takes its place. ^ * " The 
representative of the first premolar is a very small and 
simple rudiment, and is soon shed." 

Surgeon Charles Parnell, in a letter to the editor of 
"The Veterinarian" (1867, p. 287), says: 

' " In reading Prof. George Varnell's articles on some 
of the diseases affecting the facial region of the horse's 
head, 1 notice a description of wolf-teeth. He says: 
*They have been supposed to be the cause of disease in 
the eyes of horses. This idea, however, is quite erro- 
neous; therefore I shall not occupy any space in dis- 
cussing this traditional error.' Well, I can safely say 
that I have in my time extracted a great many of these 
teeth, and not merely because they existed, but because 
there was a weeping from both eyes, the cause of which 
was attributed to wolf-teeth, and generally in the 
course of a few weeks the weeping has ceased. But 
what convinces me that they do affect the eye is that 
in several cases where there were weeping and Aveak- 
ness of one eye only, I have found a wolf-tooth on the 
affected side only, and the recovery of the eye has in- 
variably followed the extraction of the tooth. The 



HORSES WITHOUT EARS. 103 

mucous membranes and lachrymal glands appear to 
be the parts affected, undoubtedly from some connec- 
tion through the nerves. If these teeth are allowed to 
remain in the horse's mouth, the sight will become 
more or less impaired." 

Might not this plan (extracting the teeth), if adopted 
by all surgeons, eventually rid horses of the so-called 
wolf-teeth? Nature may be aided or injured. The 
effect of interfering with nature is illustrated by the 
following extract from Prof. W. Youatt's work, " The 
Horse" (p. 154): 

" The custom of cropping the ears of the horse orig- 
inated, to its shame, in Great Britain, and for many 
years was a practice not only cruel to the animal, but 
deprived it of much of its beauty. It was so obsti- 
nately persisted in that at length the deformity be- 
came in some hereditary, and a breed of horses born 
without ears was produced." 

Extracting the Eemnant teeth appears to aid rather 
than injure nature. The practice is therefore as com- 
mendable as the cropping of the ears is reprehensible, 
and if the same result should follow that Prof. Youatt 
says followed the cropping of the ears, it ought to be 
adopted. 

C. D. House, an American veterinary dentist, like 
Surgeon Parnell, invariably extracts the Remnant 
teeth. He not only claims that they sometimes injure 
the eyes, but that in some cases, when they encroach 
on the maxillary branch of the fifth pair of nerves, 
they cause the horso to act as if insaiie. He saj-s he 
has more than once extracted these teeth when the 
" insane " horse was in an onen fiidd. When the tooth 



104 THE KEMN'Aiq'T TEETH. 

is drawn and tlie animal is relieyedy it looks aronnd 
and stares and acts as if wondering where it is and how 
it got there. Not more than one horse in twenty pos- 
sessing these teeth, he says, ever suffers injury to its 
eyes. 

It is notewortliy that Mr. House, who is not a regu- 
lar surgeon, has a clearer conception of the Remnant 
teeth than many who hold diplomas. However, he 
makes no distinction between supernumerary teeth 
and Remnant teeth, all being designated ^^ wolf- teeth ;" 
yet he believes the Remnant teeth to be natural teeth, 
and sa3'S he finds their germs in the cells of the jaws 
at birth. 

AVhile Mr. House was operating in Worcester, Mass., 
The Spy (newspaper) says that "in one mouth the 
wolf-teeth were found to be entirely covered by the 
gum, and detached from the jaw, so that every time 
the bit was moved they were turned, crowded, and 
jammed into the gum.'' 

Prof Williams says of Remnant teeth ("Principles 
and Practice of Veterinary Surgery," p. 479): 

'^ Small supernumerary teeth are often met with in 
front of the grinders, called Mvolf-teeth.' They have 
been supposed to be a cause of ophthalmia, but this is 
doubtful. They can produce no inconvenience ; but 
if requested to extract them a practitioner can hardly 
refuse. The best method is to remove them with the 
tooth-forceps, 

" The question as to the influence of the teeth on 
the eyes might perhaps be deemed worthy of discus- 
sion, inasmuch as the dental nerve is a branch of that 
which supplies the eyes with common sensibilit}^, 
namely, the fifth. The older writers maintained that 



MOO:!T-BLIiirD>TESS. 105 

'moon-blindness' was due to wolf-teeth, and the first 
procedure in the treatment was their removal. Now- 
adays, however, the supposition is not carried quite so 
far, and the utmost that can be said is that the irrita- 
tion of teething may be an exciting cause of ophthal- 
mia in animals whose constitutions are hereditarily or 
otherwise predisposed to the disease, and the removal 
of supernumerary teeth, or lancing the gums, may pos- 
sibly be followed by some remission of the ophthalmic 
symptoms." 

Prof. Youatt thus accounts for Eemnant teeth : 

' *'In a fev/ instances the permanent teeth do not rise 
immediately under the temporary, but somewhat by 
their side. Then, instead of the gradual process of ab- 
sorption, the root, being compressed sideways, dimin- 
ishes throughout its whole bulk. The crown dimin- 
ishes also, and the tooth is pushed out of its place to 
the forepart of tlie first grinder, and remains for a con- 
siderable time under the name o^ 2i zvolf -tooth, causing 
swelling and soreness of the gums, and frequently 
wounding the cheeks. They would be gradually quite 
absorbed, but the process might be slow and the an- 
noyance great; therefore they are extracted." 

Prof. Youatt's theory is unique, but it fails to give 
a satisfactory explanation of the "so-called wolf-teeth." 
Tliat a tooth should be pushed out of its place is sim- 
ple enough ; but why would the first upper temporary 
grinder remain in the gum and take root and the first 
lower not? That "they would be gradually quite ab- 
sorbed," is disproved by the fact that they sometimes 
persist till old age; and this fact also disproves the 
assertion that "they are extracted." Some surgeons 



106 FOSSIL HORSES' TEETH. 

do not extract them. Prof. Youatt doubtless meant 
to say tiiey should be extracted. 

As Remnant teeth are found functionally devel- 
oped in the jaws of fossil horses— in which they were 
the largest of all the teeth— a few extracts from the 
works of well-known men concerning fossil horses and 
their teeth will be appropriate as a conclusion to this 
chapter. Prof. Richard Owen says (" Odontography," 
vol. i, p. 575): 

" Cuvier was unable, from the materials at his com- 
mand, to detect any characters in the bones or teeth 
of the different existing species of Eqiius, or in the 
fossil remains of the same genus, by which he could 
distinguish them, save by their difference of size. 
Among the numerous teeth of a species of Equus as 
large as a horse fourteen and a half hands high, col- 
lected from the Oreston cavernous fissures, 1 have 
found specimens clearly indicating two distinct spe- 
cies, so far as specific differences may be founded on 
well-marked modifications of the teeth. 

" One of these, like the ordinary Equus fossilis of 
the drift and pliestocene formations, differs from the 
existing Equus caballus by the minor transverse diam- 
eter of the molar teeth ; the other, in the more com- 
plex and elegant plication of the enamel,* and in the 

* In Prof. Owen's " History of British Fossil Mammals and 
Birds" (pp. 393-4), the "elegant plication of the enamel" on 
the crown of this tooth is illustrated. Prof. Owen says : " Fig. 
153 illustrates the character, above adverted to, of the complex 
plication of the enamel, as it appears on the grinding" surface of 
a partially worn upper molar tooth, the second of the right side. 
The length of this tooth is three inches four lines, and the fangs 
had not begun to be formed. One cannot view the elegant fold- 
ings of the enamel in the present fossil teeth, and in those of 



TEETH U:N^EAETHED AT ORESTOX, EKG. 107 

bilobed iDosterior termination of the grinding surface 
of the last upper molar, more closely approximates to 
the extinct horse of the Miocene period, which Herr 
von Meyer has characterized under the name of Equus 
caballus 2irimigenius. The Oreston fossil teeth differ, 
however, from this in the form of the fifth or internal 
prism of dentine in the upper molars, and in its con- 
tinuation with the anterior lobe of the teeth, the fifth 
prism being oval and insulated in the Equus jirimi- 
geniiis of Von Meyer. 

" The Oreston fossil teeth, which in their principal 
characters manifest so close a relationship with the 
Miocene Equus primigcniiiSf differ, like the later drift 
species {Eq. fossilis), from the recent horse in a greater 
proportional antero-posterior diameter of the crown, 
and also in a less produced anterior angle of the first 
premolar. I have named this British fossil horse 
Equus 2JliGide)is. The fossil horse {Eq. curvidens) of 
South America, which coexisted with the megathe- 
rium,! and, like it, became extinct apparently before 

the more ancient primigenial species (Hippotlieria) of the conti- 
nental Miocene deposits, without being reminded of the peculiar 
character of the enamel of the molars of the Elasmotherium, in 
which it is folded in elegant festoons. This extinct pachyderm, 
which surpassed the rhinoceros in size, resembled that genus 
very closely in the general disposition of the folds of enamel in 
the grindinjT teeth, but agreed with the modern horse in the 
deep implantation of those teeth by an undivided base. The 
Elasmothere appears, therefore, to have formed one of the links, 
now lost, which connected the horse with the rhinoceros ; and 
it is interesting to observe that some of the extinct species of 
horse, in the analogous complexity of the enamel folds, more 
closely resembled the Elasmothere than do the present species." 

f " The teeth of this most g-igantic of the extinct quadrupeds 
of the sloth tribe are small in proportion to the size of the ani- 



108 FOSSIL HOES_ES' TEETH. 

the introduction of tlie human race, diff3rs from the 
exiGting horse by the greater degree of curvature of 
the upper molars." 

The following account of two fossil molar teeth of an 
extinct species of horse, discovered in South America, 
may be found in Prof. Owen's "Fossil Mammalia and 
Mammaha," (pp. 108-9) :• 

^'■Notice of the remains of a species of Eqmts, found 
associated witli tlie extinct Edentals and Toxodon at 
Punta Alta, in Bahia Blanca. and loith the Ifastodon 
and Toxodon at Santa Fe, in Entre Bios. — The first of 
these remains is a superior molar tooth of the right 
side. It was imbedded in the quartz shingle, formed 
of pebbles strongly cemented together with calcareous 
matter, which adhered as closely to it as the corre- 
sponding matrix, did to the associated fossil remains. 
The tooth was as completely fossilized as the remains 
of the mjdodon, megatherium, and scelidothere, and 
was so far decomposed that in the attempt to detach 
the adherent matrix it became partially resolved into 
its component curved lamella?. Every point of com- 
parison that could be established proved it to differ 
from the tooth of the common Equus cahallus only in 
a slight inferiority of size. 

"The second evidence of the coexistence of the 
horse with the extinct mammals of the tertiary epoch 
of South America reposes on a more perfect tooth, 
likewise of the upper jaw, from the red argillaceous 

mal. They are five in number on eacli side of the upper jaw, 
and, probably, four on each side of the lower. They present a 
more or loss tetragonal figure, and have the grinding surface 
traversed by two transverse angular ridges." — Owen. 



1^ SOUTH AMERICA. 109 

earth of the Pampas at Bojada de Santa Fe, in tlie 
Province of Entre Rios. This tooth agreed so closeiy 
in color and condition with the remauis of the masto- 
don and toxodon, from the same locality, that I have 
no doubt respecting the contemporaneous existence of 
the individual horse of which it once formed part. 
This tooth is figured at Plate xxxii, Figs. 13 and 14, 
from wliich the anatomist can judge of its close corre- 
spondence v/ith a middle molar of the left side of tlie 
upper jaw. 

"' This evidence of the former existence of a genus 
which, as regards South America, had hecome extinct, 
and has a second time been introduced into that conti. 
nent, is not one of the least interesting points of Mr. 
Darwin's paleontological discoveries.'' * 

* Mr. Darwin, in liis work on " The Descent of Man" (vol. i, 
pp. 2G0-1), says : " Although the gradual decrease and final ex- 
tinction of the races of inan is an obscure problem, we can see 
that it depends on many causes, differing in different places and 
at different times. It is the same difficult problem as that pre- 
sented by the extinction of one of the higher animals — of the 
fossil horse, for instance — which disappeared from South Amer- 
ica, soon to be replaced, within the same districts, by countless 
herds of the Spanish horse." 

In his "Journal of Researches" (pp. 130-1-2), Mr. Darwin 
gives further information concerning the fossil teeth described 
by Prof Owen, and advances a theory of the introduction of the 
horse into the " so-cilled New World." He says : " In the Pam- 
paean deposit of the Bojada I found the osseous armor of a gigan- 
tic, armadillo-like animal, tlie inside of which, when tlie earth 
was removed, was like a ^reat cauldron. I also found teeth of 
the toxodon and mastodon, and one of a horse, in the same 
stained and decayed state. The latter greatly interested me, and 
I took scrupulous care in ascertaining that it had been im- 
bedded contemporaneously with the other remains ; for I was 
not then aware that among the fossils from Bahia Blanca there 



110 FOSSIL HORSES' TEETH. 

Prof. Thomas H. Huxley says (" Critiques and Ad- 
dresses," pp. 191-5) : 

'^ Let us endeavor to find some cases of true linear 
types, or forms which are intermediate between others, 
because they stand in a direct genetic relation to them. 
It is no easy matter to find clear and unmistakable 
evidence of filiation among fossil animals. After much 



was a horse's tooth hidden in the matrix ; nor was it then known 
with certainty that the remains of horses were common in North 
America. Mr. Lyell has Litely brought from the United States 
a tooth of a horse ; and it is an interesting fact that Prof. Owen 
could find in no species, either fossil or recent, a slight but pecu- 
liar curvature characterizhig it, until he thought of comparing 
it with my specimen found here. Certainly it is a marvelous 
fact in the history of the Mammalia, that in South America a 
native horse should have lived and disappeared, to be succeeded 
in after ages by the countless herds descended from the few in- 
troduced by the Spanish colonists ! (1 need hardly state here 
that there is good evidence against any horse living in America 
at the time of Columbus). 

" When America, and especially North America, possessed its 
elephants, mastodons, horse, and hollow-horned ruminants, it 
was much more closely related in its zoological characters to the 
temperate parts of Europe and Asia than it now is. As the 
remains of these genera are found on both sides of Behring's 
Straits and on the plains of Siberia, we are led to .look to the 
northwestern side of North America as the former point of com- 
munication between the Old and the so called New World. And 
as so many species, both living and extinct, of tliese same genera 
inhabit and have inhabited the Old World, it seems most prob- 
able that the North American elephants, mastodons, horse, and 
hollow-horned ruminants migrated — on land since submerged 
near Behring's Straits — from Siberia into North America, and 
thence — on land since submerged in the West Indies — into 
South America, where for a time they mingled with the forms 
characteristic of that southern continent, and have since become 
extinct." 



HIPPARIOK AND AKCHITHERIUM. Ill 

Bearch, however, I think that such a case is to be made 
out in favor of the liorses. The modern horse is rep- 
resented as far back as the latter part of the Miocene 
epoch; but iu deposits belonging to the middle of that 
epoch its place is taken by two other genera, Hipparion 
aud Anchitherium. A species of Anchitherium was ^ 
referred by Cuvier to the Paleotheria. The grinding 
teeth are in fact very similar in shape and in pattern, 
and iu the absence of any thick layer of cement, to 
those of some species of Paleotherium. But in the 
fact that there are only six full-sized grinders in the 
lower jaw, the first prem.olar being very small; that the 
anterior grinders are as large as or rather larger than 
the posterior ones; that the second premolar has an 
anterior jDrolongation, and the posterior lower jaw has, 
as Cuvier pointed out, a posterior lobe of much smaller 
size and different form, the dentition of Anchitherium 
departs from the type of the Paleotherium and ap- 
proaches that of the horse. The skeleton of Anchi- 
therium is extremely equine. 

*'In the Hipparion the teeth nearly resemble those 
of the horse, though the crowns of the grinders are not 
so long. Like those of the hcrse, they are abundantly 
coated with cement. In the modern horse, finally, the 
crowns of the grinding teeth become longer, and their 
patterns are slightly modified." t 

Alfred Russel Wallace, F.R.aS., &c., says (^^The 
Geographical Distribution of Animals," New York 
edition, vol, i, p. 135): 

^' Ting uJata.— The animals belonging to this order 
being usually of large size and accustomed to feed and 
travel in herds, are liable to wholesale destruction by 
floods, bogs, precipices, drought, or hunger. It is for 



113 FOSSIL HORSES. 

theso reasons, probably, that tlieir remains are almost 
always more numerous than those of other orders of 
mammalia. In America they are especially abundant. 
" Tlie true horses are represented in the PUocene by 
several ancestral forms. Tlie most nearly allied to the 
modern horse is Piiohippus, consisting of animals 
about the size of an ass, with lateral toes not exter- 
nally developed, but with soma differences of dentition. 
IMext come Protohippus and Hipparion, in wdiich the 
lateral toes are developed, but are small and function- 
less, Protohippus being only two feet and a half high. 
Then we have the allied genera, Anchippus, Merychip- 
pus, and Hyohippus, which were still smaller animals. 
In the older deposits v*^ come to a series of forms, still 
unmistakably equine, but w^ith three or more toes used 
for locomotion, and v/ith numerous differentiations in 
form, proportions, and dentition. In the Miocene we 
have the genera Anchitherium, Miohippus, and Meso- 
hippns, v\^ith three toes on each foot, and about the 
size of a sheep or large goat. In the Eocene of Utah 
and Wyoming we get a step luither biick, several spe- 
cies having been discovered abjut the size of a fox, 
with four toes in front and three behind. These form 
the genus Orohippus, and are the oldest ancestral 
horse known." 

The following account of a horse's tooth that was 
found while digging a well is from The Popular Science 
Revieiu : 

"In a paper read before the St. Louis Academy of 
Science, and reported in The American NaturaUst for 
March, 1871, Mr. G. 0. Broadhead records some in- 
teresting facts about fossil horses. Alluding to the 
fact that horse remains have been found in the altered 



A TOOTH FOUND IN DIGGING A WELL. 113 

drift of Kansas, he says he is now able to announce 
that similar remains have been discoveredm a well at 
Papinville, Bates County, Mo. Mr. 0. P. Ohhngei^ 
while dioging a well, unearthed a tooth at a depJi ot 
thirty-one feet from the surface ; it was restmg m a 
bed of sand beneath a 4-iDch stratum of bluish clay 
and 2'ravel. Beneath the sand containmg the tooth 
was a gravel-bed five feet in thickness. He sent the 
tooth to Prof. Joseph Leidy, of Philadelphia, who pro- 
nounced it to be the last upper molar of a horse, prob- 
ably an extinct species." 

In various volumes of the " Proceedings of the Acad- 
emv of ^^atural Sciences of Philadelphia," accounts oi 
many other fossil horses' teeth may be found, ot which 
the following is a specimen (" Proceedings," &c., 1871, 
p. 113): 

'^Prof. Joseph Leidy exhibited a specimen of an 
upper molar tooth, which Mr. Timothy Conrad had 
picked up from a pile of Miocene marl at Greenville, 
Pitt County, K C. He believed, from its size and the 
intricacy in the folding of the enamel of the islets at 
the middle of the triturating surface, that the tooth 
belon-ed to the Post-Pliocene Equus complicatus, and 
was an accidental occupant of the Miocene marl. It 
mioht, however, belong to a Hipparion of the Miocene 
period, but the imperfection of the specimen at its in- 
ner part prevented its positive generic determination/' 

In the Proceedings of the same Society for 1854-5 
(p. 340) is an account of the fossil remains of an am- 
mal as unlike the genus man as man is unlike the 
ornithorhynchus. Its exhumation and subsequent 
exhibition in New Orleans created botii interest and 



114 TEETH WEIGHING TWO POUNDS. 

merriment at the time, for it was not then known that 
the Americas are not only the richest in fossil animal 
remains of all the continents, but are probably the 
first that were inhabited by man. The record is as 
follows : 

" Dr. Joseph Leidy stated that he had received from 
Dr. 'Nott the bones of the so-called fossil man, exhib- 
ited in New Orleans several years since. The skeleton 
was eighteen feet in length. There were two molar 
teeth, each weighing two pounds, and the fragment of 
a canine. The bones are those of the mastodon." 



CHAPTER VI. 

DENTAL CYSTS AND SUPERNUMERARY TEETH. 

Teeth growing in various parts of the Body. — Some Cysts more 
Prolific than others, Producing a Second, if not a Third, 
"Dentition." — Reports and Theories of Scientific Men. — 
Cases of Third Dentition in Human Beings. 

The developmerit of abnormal teeth in different 
parts of the body (the human body as well as those of 
the lower animals, particularly the horse), is not the 
least interesting feature in the study of dental science. 
To judge from the reports that follow, one would think 
the tooth-substance in some horses w^as an unknown 
quantity. It would be interesting and useful to know 
whether in such cases the natural teeth are in a per- 
fectly healthy state, and whether the temperature is 
natural, instead of being increased, as during certain 
periods of teething. While the study of these teeth 
may not be of paramount importance, it serves to 
further illustrate the physiological relations of the den- 
tal system, and ought to assist the surgeon in more 
correctly diagnosing diseases. 

Surgeon George Fleming, of the Ro3'al Engineers, 
contributed a valuable paper entitled '• Dental Cysts, 
or Tooth-Bearing Tumors,*' to *'The Veterinarian" for 
1874 (p. 692), the substance of which is as follows: 

*^ In The Gazetta Medico- Veterinaria of Milan for 
1873 (p. 274), Profs. Limzillotti-Buonsanti and Gui- 



116 DEXTAL CYSTS. 

seppe General!, of the Veterinary School of that city, 
published a most complete and interesting contribu- 
tion to our knowledge of the pathology of dental cysts 
in the horse, well illustrated with wood-cuts, and in- 
cluding a full bibliographical record and synoptical 
table of these morbid productions. From their re- 
searches it would appear tliat dental cysts were first 
described by Mage Grouille, in 1811.* 

" These teeth-bearing tumors have received different 
names. Thus they have been designated 'erratic' or 
'misplaced teeth,' 'dental neoplasies,' 'odontocysts,' 
'dental degeneration of tlie temporal bone,' 'temporal 
fistula,' 'abnormal development of teeth in unusual 
places,' 'auricular teeth,' 'odontocele,' and 'dentiger- 
ous cysts' or 'teetli tumors.' They may be developed 
in unusual places, such as the temporal region, the 
frontal bones, the hase of the ear, the space between 
the branches of the lower jaw, the lumbar region, the 
testicles, and the ovaries. Coleman stands alone in his 
case of a cyst found beneath the right kidney, in which 
were two small molars and an incisor, attached to a 
bone that resembled a jaw, though the Milan profes- 
sors believe the teeth in this instance may have been 
developed in a testicle retained in the abdominal cav- 
ity. The most common situation is undoubtedly in 
the temporal region, as in seventy-nve recorded cases 
sixty-eight Avere observed there. These cases all refer 
to the horse. Berger-Perriere, however, found a tem- 
porary incisor in a fistulous vfound near the right ear 

* "No mention is made of the Ahhr/evo/iefol iv role yrudoic, or 
niaxillaiy exostoses of Apsyrtus (' Hipp. Gr.' p. G4\ wlio recom- 
mends tliat these tumors sliould be carefully and completely 
removed, or thoy will return -of a larger size." 

Th3 reference note is a -so Suro-eon Flemin<r's. 



A CYST 3IISTAKEIS" FOR GLAXDEBS. 117 

of a lamb two months and a half old ('Recueil de 
Mod. Veterinaire,' 1835, p. 586). 

'•'In most instances only one tooth is found. Gurlt 
was the first to find, on the mastoid process of the 
temporal bone, a mass of molar teeth fused, as it were, 
together. Tlie tumor was three inches and a half 
hio'li, and about two in its lar<2:est diameter. The horse 
had been destroyed for glanders. Goubaux found two 
at the posterior portion of the sphenoid bone, and Bay 
four. In a cyst of the testicle Gurlt discovered six 
teeth, three separate and three in a mass. Bay at- 
tended a horse in 1800 that appeared to be suffering 
with encephalitis. It died twenty-four hours after his 
visit. It had always shown, on the right temporal re- 
gion, a tumor without a fistula, but it did not attract 
notice, as it apparently caused no inconvenience. Nine 
years afterward, when Bay was preparing tlie head as 
a pathological specimen, he discovered this supposed 
exostosis to be constituted by the union of four molar 
teeth. The two superior teeth projected from the 
temporal articulation, and the inferior tvvo w^ere situ- 
ated in the petrous portion of the temporal bone, in- 
clining obliquely from within outward. The posterior 
portion of the latter projected in a very salient manner 
at the seUa furcica, and must have produced much 
pressure on important parts of the brain. 

"Age does not appear to have any iufluence on the 
development of these cysts, the animals in which they 
have been observed ranging in age from eight or nine 
months to fifteen years. The period of formation also 
varied greatly. lu regard to the side of the body in 
"which they Avere developed, in seventeen cases they 
were on the left, and in tlvirteen on the right. In 
fourteen cases oboCrved by Macrops, they were indifier- 



118 DENTAL CYSTS. 

ently on both sides. In this respect clinical observa- 
tion has not yielded any fact of practical importance. 

"Sometimes, after the extraction of a tooth, it hap- 
pens that the cavity of the cyst or the bottom of the 
fistula does not cicatrize. This is a sure indication 
that a new tooth is formins:. Rodet noted this fact as 
long ago as 1827. Macrops has observed a case of this 
kind. He was compelled to operate twice within three 
months, each time removing a molar tooth; and when 
he made his report, in 1860, it was probable that a 
third tooth was being developed, as the fistula had not 
closed." 

Surgeon Fleming also mentions cases that were ob- 
served by Surg"eons Perosino, Martin, Harold, Gamgee, 
Coclet, Lafosse, and others. He continues: 

"Profs. Lanzillotti-Buonsanti and General! made 
minute inspection of a specimen of tooth taken from 
the base of the ear of a foal twenty months old, and 
they report that microscopically the structure of such 
teeth does not differ much from natural teeth. The 
same constituents — dentine, enamel, and cement — 
were found, the only difference being that they were 
arranged in an unusual manner. In the tooth they 
examined, for instance, the cement v^^as abundant in 
the central part, while in that studied by Oreste and 
Falconio, the dentine was most abundant and the 
cement least in quantity." 

Surgeon Fleming next refers to and gives a sum- 
mary of the views of scientific men, who say that "A 
certain number of teeth may sometimes be developed 
as parasitic productions in a cavity similar to and situ- 
ated near the mouth (in which category is included 



A FETUS WITHIJ^ A FETUS. 119 

the excellent case occurring in a woman, and de- 
scribed, in 1862, by Prof. Generali — an observation 
unique in the teratology of mankind — namely, a 
case of parasitic monstrosity, in which, however, the 
designation 'dental cyst,' so inexact in itself, is in- 
appropriate a;id false);" that "the ovarian cysts in 
women, in whicli have ])een found pieces of bone and 
cartilage, teeth, and a lower jaw, more or less de- 
formed, ought to be considered as probable cases of 
ovarian impregnation with an incompletely developed 
fetus, and in young girls as examples of the intra- 
uterine formation of a fetus within a fetus;" that 
"only in this way can be explained the lipomatous 
and sarcomatous congenital masses contained in cysts, 
with the teeth and fragments of bone simulating an 
incomplete jaw, which have been observed on the 
human orbit (Lobstein and Travers), on the palate 
(Otto), on the tongue (Stansky), on the side of the 
jaw, in the cheek, and on the neck, but which Schultze 
and Panum consider as the simple proliferation of em- 
bryonic plasmatic cells;" that "some dental cysts are 
true dermoid cysts, containing hair and teetli," &c., 
and closes his paper with the following common-sense 
suggestion : 

" Perhaps direct researches, which have not yet been 
made, carried out in favorable circumstances, will bet- 
ter serve in deciding their real nature than all the 
more or less brilliant academical reasoning." 

John Gamgee, Professor of Anatomy and Physiology 
in the Edinburgh Veterinary College, in the course of 
a series of articles on various subjects in " The Veter- 
inarian " for 185G, tlnis comments on a case of dentig- 
erous cyst, the history of which was originally written 



120 DENTAL CYSTS. 

by Monsieur Lafosse and published in tlie "Journal 
des Veterin-iire da Midi:" 

*'3I. LafossG, Professor of Clinical Medicine in the 
Veterinary School of Toulouse, had under his treat- 
ment a four-year-old rnaro that for two months before 
admission into the infirmary was affected with a phleg- 
monous tumor in the re.f^'ion of the left ear. This was 
opened. The wound that resulted rapidly contracted, 
but a fistula remained. When Lafosse first saw the 
case, he found a painful tumor, vv'ith a granulating 
wound just behind the scutiform cartilage, and near 
the upper part of the parotid gland. By probing he 
ascertained that at the bottom of the fistulous tract 
was some hard substance, Avhich he supposed to be the 
Bcutiform cartilage in an ossified state, or a portion of 
the temporal bone exfoliating. A severe operation 
was performed, and the solid substance extracted. It 
w\as double, deeply seated, and firmly adherent to sur- 
rounding textures. Slight hemorrhage ensued from 
the division of the anterior auricular, but w^as casilv 
stopped. Tiie wound was dressed, and the animal 
soon recovered, having shown only a few symptoms of 
sore throat after the operation, 

'- 1 shall not translate M. Lafosse's description of 
the products he extracted. They were composed of 
tooth-substance, and althougii it has been questioned 
Y/hether it is real tooth that is developed in the shape 
of accidental growths in the region of the ear, still the 
fact is now well established, however puzzling to the 
minds of some it may be to comprehend their origin. 

" Lafosse attempts a teratological explanation, but 
asks : ^ If teeth are looked on as arising from the tegu- 
mentary system, considering them in mo&l: animals as 



TEETH EMAJn'ATIIfG FRO:.I OSSEOUS SYSTEM. 121 

emanating from papillae and mucous membrtine, where 
was the dormoid papilla that constituted the basis of 
development of this tooth, deeply seated and close to 
the ear, especially as what might be taken as the 
crown looked toward the inner surface of the skin?^ 

*' Further on Lafosso show^s that iu certain animals 
teeth absolutely emanate from the osseous system, as 
in the eolith:}' scaicr and other serpents, in which true 
osseous eminences, coated by enamel, pierce the esoph- 
agean tunics, and project into the tube; they are at- 
tached to about thirty vertebra3, of which they form 
the inferior spinous process. These are intended to 
crush the eggs that the serpents feed upo». 

^' Having established the fact that teeth may spring 
from bone as well as mucous membrane, Lafosse leads 
us, where we never suspected, to consider the dental 
tumors above spoken of as congenital, and he looks 
on them as having sprung from some rudiment of a 
maxillary bone. In a word, he looks on the abnormal 
tooth in question — without offering any plausible ex- 
planation — as an aberration in development. He does 
not class such teeth with the teeth formed iu the 
ovary, &c., but rather with those instances where an 
extra limb or portion of an extremity is to be met with. 
It is an accidental excess of parts in an otherwise well- 
formed bod}^ ^It cannot,' sn^js Lafosse, ^be looked on 
as an osseous transformation of certain tissues.' 

"I have spoken of the case at bngth, for surgically 
it is of the very greatest interest. As pathological 
anatomists, it is our duty to study the laws of disease 
as v;eil as health. It is praisew^orthy to dive into the 
mvsterios of the ori^-in of monsters, but it is essential 
to adhere to facta and not sacriiioe them to theoretical 
explanations, 
6 



122 DEKTAL CYSTS. 

" In common with others, I have studied several of 
these dental tumors. They may spring from several 
of the bones of the head, but especially from the region 
of the petrous temporal bone. They may project to- 
ward the interior of the cranium, but tliey more fre- 
quently project outwardly. They may be strongly 
implanted in the bone, or get separated; then they 
are maintained in their situation by the soft textures 
around. Their development is not more extraordinary 
than that of other osseous growths that spring from 
the cranial or maxillary bones ; and their tooth-formed 
structure (teeth in the region of teeth), is not more 
wonderful than hony tumors in other parts of the sys- 
tem, whether connected or not with the skeleton." 

Prof. William Sewell, President of the British Vet- 
erinary Medical Association, at the meeting of that 
body on May 15, 1838, advanced an interesting theory 
of the growth of abnormal teeth. It may be true, for 
after the teeth have attained their full grow^th, it is 
reasonable that the dental arteries are less active. But 
as the teeth continue to grow throughout life, a fact 
Prof. Sewell does not mention, it is not so reasonable 
that they even "in a manner cease" to act. The pro- 
fessor's remarks are thus reported ("Veterinarian," 
1838, "Proceedings Vet. Med. Ass.," p. 199): 

" The President begged leave to direct the attention 
of the meeting to a horse's tooth that had been pre- 
sented to him. It was a fine specimen of the anomaly 
occasionally observed in the dental system of the liorse 
— the production of teeth in other places than the 
alveolar cavities, after the natural teeth had been per- 
fected. The situations which I^ature in her wander- 
ings selected were occasionally very singular. He had 



TEETH LIKE A CALF'S TOUNG HORN. 123 

seen a tooth wliicli grew from tbc petrous portion of 
the temporal bone, like a young liorn from the fore- 
head of a calf. It formed a hard and seemingly very 
painful tumor, which was ultimately opened, and the 
bony substance, which proved to be an almost perfect 
tooth, extracted. He had seen three or four similar 
cases in which teeth had been thus produced. When 
the dental arteries in a manner cease to act— the teeth 
bavin o- attained their full growth— there was a singu- 
lar predisposition in the neighboring arteries to take 
on the same action, and teeth, more or less perfect, 
were formed in parts altogether unconnected with den- 
tition. In this case there were two, one on either side 
of the forehead." 

Suro-eon F. Denenbourg makes a detailed report in 
« The Veterinarian" for 1869 (p. 533) of six cases of 
dental cyst, five of which he operated on successfully. 
The first case he treated was in 1837. He confesses 
that he believed them to be mucous tumors till 18ol, 
when he found a molar tooth perfectly formed. This 
tooth which was deposited in an anatomical museum, 
was a^ large as a pigeon's egg, and had three roots. 

Surgeon C. C. Grice, of New York, makes the fol- 
lowing report ("Veterinarian," 1867, p. 392) : 

"Whether the case the facts of which I am about to 
communicate will prove of sufficient interest to be pre- 
sented to the notice of the veterinary profession, or 
will add anything to the advancement of veterinaiy 
pathologv, I know not; yet I would be glac to see it 
inserted 'in our respectable old journal, ' The Veteri- 
narian,' for I hold it to be the duty of every member 
of the profession to advance its interests to the bestot 



124 DEKTAL CYSTS. 

his Libility. I send it because to me it is a yery rare 
case. I have now been in practice more than forty 
years, and I have not met with anything of the kind 
before. 

" At the request of Mr. Barnum, a merchant of our 
city and the owner of a breeding-farm in Westchester 
County, I attended a two-year-old colt, considered to 
be very valuable, as he comes from trotting stock. Mr. 
Barnum merely said the colt had a discharge from the 
base of the near ear, and that it had existed for ten 
months. 

'' I found the animal so very shy on account of the 
previous torturing of his attendants, that I could not 
approach him ; therefore I had to cast him. The in- 
troduction of the probe failed to satisfy me that any 
foreign body existed there; but on dilating the orifice 
and introducing the most reliable of all probes, my 
forefinger, I discovered a hard substance, v/hich was 
firmly attached to the temporal bone and surrounding 
parts. I could not grasp the substance with the for- 
ceps, therefore I used the handle of the instrument as 
a lever, and after using great force dislodged it. Mr. 
Barnum picked up something in the grass four or five 
yards from me, and it proved to be a molar tooth. On 
examining the wound afterward I found some loose 
fragments of bone, and on removing them they ap- 
peared to be the socket of the tooth. 

'' I would have sent you a report of this case earlier, 
but I was desirous of seeing its termination. Mr. Bar- 
num says the parts have entirely healed and left no 
blemish." 

Prof William Williams advances an interesting the- 
ory regarding the cause of dental cysts and also the 



AMAUROSIS AND ATROPHY OF THE EYES. 125 

manner of their formation. He saj^s (" Principles and 
Practice of Veterinary Surgery," p. 412) : 

" Cysts containing teetli have been found in the tes- 
ticles and other parts of the body, but those which are 
of importance to practical men are found within the 
antrum. I hav^e seen several cases of this kind, and 
have extracted teetli from cysts even so high as the 
base of the ear. 

"During life these tumors are distinguishable by 
more or less disfigurement of the face, by a bulging out 
of the superior maxillary bone, accompanied in some 
cases by amaurosis of one eye, succeeded by atrophy 
of the eye from the pressure of the growing tumor. 
In other cases these complications are not present, but 
now and then an abscess forms in the post-orbital re- 
gion, which will be found on examination to contain a 
hard body — an imperfect tooth. 

" To understand the process by which these tumors 
are formed, it is necessary to remember that the teeth 
of all animals belong to and arise from the membran- 
ous portion of the digestive canal, and that at a very 
early period of fetal life a provision is made for the 
development of the permanent teeth as well as the 
temporary. This provision, according to Goodsir, is 
as follows : * As early as the sixth week of intra-uteral 
life (human), a groove appears along the border of the 
future jaws, called the primitive dental groove, which 
is lined by the membrane of the mouth. At the bot- 
tom of this groove projections — papillae — spring up, 
corresponding in number with the temporary teeth. 
AYhile the growth of the papilla) is going on, partitions 
are formed across the grooves, by which they become 
separated from each other. These partitions subse- 



126 DENTAL CYSTS. 

quently form the bony sockets, thus placing each 
papilla in a separate cavity. Concurrent with this 
process, small growths take place upon the membrane 
of the mouth, just as they dip into the papillary cavity 
or follicle, which finally, by union with other growths, 
form a lid which covers the papillse in a closed sac or 
bag. Before the final closing of the follicle, a slight 
folding inward of its lining membrane takes place. 
This inward folding of the membrane of the primitive 
groove is for the purpose of forming a new cavity — the 
cavity of reserve — which furnishes a delicate mucous 
membrane for the future formation of the permanent 
teeth. The cavity in which the permanent tooth is 
developed is a mere detachment from the lining of the 
primitive groove, and in it a papilla is formed in the 
same way as that of a temporary tooth/ * 

" ]^ow, I look on the formation of these tumors as 
being due to some irregularity in this folding of the 
lining membrane, by wiiich the * cavity of reserve' is 
made up of several folds ; that these folds eventually 
become separated, forming separate cavities of reseiTe, 
and that a papilla similar to those of the natural teeth 
is developed in each cavity. These irregular papillae 
are converted into irregular teeth, whicli, for want of 
space in the mouth, are forced into the antrum, and 
may completely block it up, as well as the posterior 
nasal opening. 

" I have classified them as cystic tumors, as at first 
they are inclosed in sacs or cysts. They soon burst 
through their investing membrane, however, and form 
a large tumor, composed entirely of teeth, having a 

* Compare Professor Goodsir's theory with those advanced 
by Messrs. Oweu, Tomes, Chauveau, and others in the first 
chapter. 



A BULL WITH AI<r UPPER IJfCISOR. 127 

great variety of shapes, and ranniiig in different direc- 
tions. The teeth vary in size, some being very small, 
while others are nearly as large as a permanent grinder. 
Each tooth has a pnlp cavity, and is composed of the 
same substances as the natural teeth. Should their 
removal be desirable, it will be necessary to trephine 
the superior maxillary sinus and detach them with the 
forceps.'' 

In the chapter entitled "The Pathology of the 
Teeth" (the VIII.), Surgeons Bouley and Ferguson, 
in the course of their memoir on horses' teeth, record 
some important facts about supernumerary teeth. In 
one animal the rows of grinders are said to appear 
double. The facts are given in that particular chap- 
ter in preference to the present one in order that the 
memoir may have a connected reading. 

M. Roche Lubin gives the following account of a 
tooth that he extracted from the upper jaw of a young 
bull ("Le Zooiatre du Midi," February, 1838): 

" On the 14th of April, 1837, I was requested by M. 
Bonhome, wiio lives near Rhodez, to extract a tooth 
which was growing in the middle of the palate of his 
young bull. The novelty of the thing made me hasten 
to comply with his request. The animal being secured, 
I removed the tooth in the usual way. A very consid- 
erable hemorrhage followed its extraction, which was 
performed with some difficulty on account of the tooth 
being firmly implanted in the palatine arch. It was 
situated at the middle of the median line, and was of 
precisely the same character as tluat of the usual incisor 
tooth of the ox. This is, I believe, the only case on 
record, the incisor teeth being wanting in the upper 
jaw of cattle." 



128 SUPERNUMERARY TEETH. 

Human beings, like the lower animals, are now and 
then afflicted with a superfluity of tooth-substance, or 
at least they have supernumerary teeth. John Hunter 
says (" The Human Teeth," p. 53) : 

'^ We often meet with supeninmerary teeth, and this, 
as well as some other variations, happens oftener in 
the upper than in the lower jaw, and, I believe, always 
in the incisors and cuspidati. 1 have only met with 
one case of this kind, and it was in the upper jaw of a 
child about nine months old. The bodies of two 
teeth, in sliape like the cuspidati, v^'ere placed directly 
behind the bodies of the two first permanent incisors; 
so tiiat there werc three teeth in a row, placed behind 
one another, namely, the temporary incisor, the body 
of the i^ermanent incisor, and that supernumerary 
tooth. The most remarkable circumstance was that 
these teeth v.'ere inverted, their points being turned 
upward and bent, caused by the bone which was above 
them not giving way to their growth, as the alveolar 
process does." 

The following account of cases of third dentition in 
liuman beings is from "Bond's Dental Medicine" 
(p. 21G): 

"Third Dentition. — A number of well authenticated 
cases of partial and even complete dentition, occurring 
in very old persons, are recorded in the books. In one 
instance, given in the 'Edinburgh Medical Com.' (vol. 
iii.), the patient, who was sixty years old and entirely 
toothless, suflTerecl very severely. At the end of twenty- 
one days from the beginning of his sufferings, however, 
he was compensated by the appeojcance of a complete 
set of new teeth. 



THIKD DEXTITIOIsTS FATAL. 129 

" With regard to tlie constitutional effects of this 
abnormal dentition, Prof. Harris, who relates two 
cases as having occurred under his own observation, 
says : 'It seems that the efforts made by nature for the 
production of a third complete set of teeth are usually 
so great that they exhaust the remaining energies of 
tlie system, for occurrences of this kind are generally 
soon followed by death.' " 



CHAPTER YII. 

HORSES' TEETH UKDER THE MICROSCOPE. 

The Dentinal Tubes, Enamel Fibers, and Cemental Canals De- 
scribed and Contrasted. 

Prof. Richard Owen's description of the micro- 
scopical appearance of horses' teeth, like the extracts 
already made from his works, is both interesting and 
profound. The teeth described are illustrated in the 
second volume of the " Odontography," the section of 
the molar being magnified three hundred linear diam- 
eters; that of the incisor, however, is not magnified. 
In the first volume (pp. 576-7-8) Prof. Owen says: 

"The body of the long molar teeth of the horse 
consists of columns of fine-tiibed, unvascular dentine, 
coated by enamel, which descends in deep folds into 
the substance of the teeth. The enamel is covered 
by cement, thickest in the interspaces of the inflected 
enamel-folds and upon the crowns of the molars, where 
it is permeated by vascular canals, thinnest on the 
crowns of the canines and incisors. At the roots of 
these teeth, aiid on those developed from the w^orn- 
down molars, the dentine is immediately invested by 
cement. 

*^ In a vertical section of the incisor, as in Plate 136, 
Fig. 11, the pulp-cavity, contracting as it approaches 



TUBES DICHOTOMOUSLY BRAi^CHED. 131 

the vertical enamel-fold, divides near the end of that 
fold, and extends a little way between it and the 
periphery of the incisor, or leaves a few medullary 
canals and a modified thin tract of irregularly formed 
dentine between the reflected and the outer coat of 
enamel, but rather nearer the former. Above this 
tract, near the summit of the crown, the dentinal tubes 
proceed in a nearly vertical direction, with a gentle 
sigmoid primary flexure, where they diverge from the 
perpendicular. Lower dow^n they diverge in opposite 
directions, curving from the remains of the pulp- 
fissure toward the outer and the inner enamel, and are 
described by Eetzius as being in the form of the Greek 
e; but the course of two distinct series of dentinal 
tubes, and not of a single tube, is illustrated by this 
comparison. AVhen the pulp-cavity couies single and 
central, as at the lower half of the tooth, the tubes 
diverge to the periphery, with one principal primary 
curve, convex toward the crown. Each tube is bent 
in minute secondary gyrations to within a short dis- 
tance of its peripheral termination, where it is much 
diminished in size, and is dichotomously branched. 
The tubes at their beginning form the upper calcified 
tracts of the pulp-cavity, which usually retain some 
remnants of that vascular receptacle in the form of 
medullary canals, and are strongly and irregularly 
flexuous before they fall into the ordinary primary 
curves. These tubes, proceeding toward the inner 
reflected folds of enamel, are more vertical than the 
tubes going to the periphery. 

''A transverse section of the incisor of a young horse 
or ass, taken across the part marked a in Fig. 11, shows 
a long oval island of vascular cement in the center, 
bounded by a border of enamel, with an irregular ere- 



132 HORSES' TEETH UNDER THE MICROSCOPE. 

nate edge next the cement, and an eyen edge next the 
dentine, which is here clearly seen to be divided into 
an inner and an outer tract by an irregalar series of 
the vascular canals continued from the summit of the 
pu]p-eavity, and by the irregularly tortuous dentinal 
tubeSj which, with the canals, indicate the last con- 
verted remnant of the pulp in this part of the crown. 
The inner tract of dentine next the island of enamel 
is well defined, and a little broader than the secretion 
of the enamel itself, and shows the extremities of the 
tubes cut transversely, which, as before observed, were 
at this point directed chieHy in the axis of the incisor 
toward the v/orking surface of the crown. The tubes 
in the outer tract of dentine, inclining more toward 
the sides of the toothy are more obliquely divided, and 
at the ends of the section they are seen lengthwise, ele- 
gantly diverging toward the sides of the section. This 
tract of dentine is bounded externally by a layer of 
enamel, one-sixth part thicker than that forming the 
central island; and the enamel is coated by an outer 
layer of cement, of its own thickness at the sides, but 
thinning off at the two ends of the section. Tlie den- 
tinal tubes proceeding from the residuary pulp-tract 
make strong and irregular curvatures, diverging to 
include the divided areas of the vascular canals, and 
in the outer layer, at one side of the section, they de- 
sctibe strong zigzag curves at the middle of the outer 
division of the dentine. 

''The diameter of the dentinal tubes at their central 
and largel' ends is pretty regular, about go^op th of an 
inch ; at the middle of their course, -gVo "o^^^^ ^^ ^^ inch, 
thence decreasing, and very rapidly, after the terminal 
bifurcations begin. The tubes are separated from one 
another by intervals varying between once and twice 



THE CURVES OF THE DENTINAL TUBES. 133 

their tliickness. In some parts of the dentine of the 
incisor they are more closely crowded together, espe- 
cially near their origin from the pulp-cavity. Their 
secondary gyrations describe a cnrve of about yy^-oth 
. of an inch in length. These subside in the slender 
terminations of the tubes, which bifurcate dichoto- 
mously once or twice, and send off small lateral 
branches near the enamel. The small lateral branches 
are chiefly visible in the peripheral third part of the 
tubes, and are sent off at very acute angles, except in 
the strongly and irregularly bent origins from the 
j)ulp-tract. I have never seen these small branches of 
the dentinal tubes terminating in radiated cells, like 
those of cement and bone, as Retzius describes; but 
the peripheral smallest branches near the enamel occa- 
sionally dilate into corpuscles much more minute 
than the radiated cells, as they do in the teeth of most 
quadrupeds. 

"The dentine, as seen in a longitudinal section of 
the crown of a molar, by a magnifying power of three 
hundred linear dimensions, is figured at a, Plate 137. 
The tubes are hero separated by rather wider inter- 
spaces than those of the incisor, and do not decrease 
in size so rapidly. The convexity of the terminal bend 
of the tubes is turned toward the summit of the crown. 
In the incisor, the clear dentinal cells are very small 
near the peripheral part of tlie dentine, but increase in 
size as they approach the pulp-cavity. They are of a 
sub-circular figure, with bright, transparent lines. 

"The central cement in the crown of the incisor is 
permeated by vascular canals, separated by intervals of 
from two to three times their own diameter, directed 
in the middle of the substance in the axis of the tooth, 
but diverging like rays obliquely toward its periphery. 



134 horses' teeth under the microscope. 



The clear substance forming the walls of the canals is 
arranged in concentric layers, the thickness of the 
walls being about equal or rather less than the area of 
the canal. The radiated cells, generally of a full oval, 
sometimes of an angular form, are chiefly dispersed in 
the interspaces of the vascular canals, and with their 
long axis parallel with the j^lane of the layers of the 
coats. The finer system of tubes radiating from the 
cells, and corresponding by minute branches from the 
vascular canals, freely intercommunicate. In the 
peripheral cement of the incisors examined by me, I 
found no vascular canals, but only the radiated cells, 
and the fine tubuli which I have called 'cemental,' 
and which traverse the cement at right angles to its 
plane, and communicate with the tubes radiating from 
the cells. These are more usually elliptical than in 
the thicker central cement, their long axis being par- 
allel with the borders of the cement. They are most 
abundant next the enamel, and rarely encroach upon 
the clear peripheral border of the cement. The exte- 
rior coronal cement of the molars (Plate 137, c), is as 
richly permeated by vascular canals (v v), as is the 
central cement of the incisor. 

*'The enamel-fibers of the horse's incisor are very 
slender, not exceeding twice the diameter of the denti- 
nal tubes. They extend, with a single sigmoid curve, 
through the entire thickness of the layer, contiguous 
fibers curving in opposite directions. The peripheral 
border, or that next the cement, is everywhere indented 
with hemispherical pits from -g-Jir^'^^ ^^ iroVo^^^ ^^ ^^ 
inch in diameter, from four to six of the radiated cells 
of the cement being often clustered together in the 
larger depressions. The inner or dentinal border is 
nearly even and straight; here are seen the short 



CLEARNESS Oi* THE EKAMEL- FIBERS. 135 

cracks or fissures extending into the enamel. The 
fibers are rather more wavy in the thicker enamel of 
the molar teeth (Plate 137, §). 

*^If the enamel is viewed in sufficiently thin sec- 
tions it is free from those wavy, dusky markings which 
are produced by the more tortuous fibers of the human , 
enamel; and I have been unable to distinguish any 
transverse striae in the fine fibers of that tissue in the 
horse. The appearance of such is given by thicker 
sections of the enamel-fibers taken obliquely across 
them, and is produced by the cut ends of the fibers." 



CHAPTER VIII. 

THE PATHOLOGY OF THE TEETH. 

Importance of the Subject. — Caries caused by Inflamed Pulps, 
Blows, Virus, and Morbid Diathesis — Supernumerary Teeth 
and other Derangements. — Trephining the Sinuses. — Gutta 
Percha as a Filling. — Cleaning the Teeth. — A Diseased Fos- 
sil Tooth. 

The importance of the study of the pathology of 
the teeth is self-evident, for they not only bear iinpor- 
tant relations to the general system, but, like all other 
parts of it, are subject to disease and derangement. 
The fact that disease of tlie teeth is involved in more 
or less mystery, is an argument in favor of the study 
of the subject, for, to use Surgeon Gamgee's words, 
it is a "duty to study the laws of disease as well as 
health," and "it is praiseworthy to dive into the mys- 
teries of the origin of" diseases as well as monsters. It 
is probably not too niuch to say that, to the successful 
surgeon, knowledge of the diseases and derangements 
of the teeth is indispensable. 

In order to facilitate the study of and cast light on 
the subject, I have brought into juxtaposition, as it 
were, a summary of the views of a few able men in 
regard to the cause of caries, &c., which, better still, is 
followed by the reports of well-known surgeons, who 
give the results of their experiences in detail. 



DECAY, EXOSTOSIS, AND ABSCESS. 137 

Prof. Richard Owen says: 

"A tooth, when fully formed, is subject fco decay, but 
has no inherent power of reparation. '•' ''' '^ ^In 
growing teeth, with fangs not fully formed, the cement 
is so thin that the Purkinjean cells are not visible. It 
looks like a fine membrane, and has been described as 
the periosteum * of the fangs ; but it increases in thick- 
ness with the age of the tooth, and is the seat and ori- 
gin of what are called exostoses of the fangs, which are 
wholly composed of it.' These growths are subject to 
the formation of abscess, and all the morbid actions of 
true bone.'' 

Speaking of a diseased fossil (horse's) tooth, Prof. 
Owen says: 

"But the cavity had evidently been the result of 
some inflammatory and ulcerative process in the origi- 
nal formative pulp." 

Dr. Boon Hayes says : 

"I think it would not be difficult to prove that 
caries of the teeth more frequently proceeds from in- 
flammation beginning in the pulpal cavity than from 
any other cause." 

Dr. Robley Dunglison says: 

"The most common causes of caries are blows, the 
action of some virus, and morlnd diathesis." 

* Surpreon John Hughes say? : " The iieriosteum of the teeth 
is not supplied with blood in the way the same membrane in 
other parts of the body usually is. It is sup])lied by means of 
vessels coming from the pulp of tlie tooth." If this is true, then 
it would be easy for inflammation to be conveyed from one to 
the other. 



138 THE PATHOLOGY OF THE TEETH. 

" Odontonecrosis " is defined by him as " dental gan- 
grene/*' and ''Odontrjpy" as "the operation of perfo- 
rating a tootli to evacuate the purulent matter con- 
fined in the cavity of the pulp" (pulpal cavity). 

Prof. William Percivall, referring to two diseased 
grinder teeth (horses'), says: 

" They seemed to have been cases which had origi- 
nated in internal injury." 

Surgeons Bouley and Ferguson say: 

"In explaining caries of the teeth, we cannot invoke 
the aid of inflammation and the modifications wdiich 
it induces in the tissues it attacks; nor can we say- 
that inflammation implies an active circulatory move- 
ment, an afflux of liquid, an alteration, nervous de- 
rangement, &c." 

Possibly the gentlemen were not aware of the in- 
flammation that Prof. Owen says may exist "in the 
original formative pulp," and of that of "the pulpal 
cavity" — the pulp in the cavity of a full-grown tooth — 
mentioned by Drs. Hayes and Dunglison. Are not 
such inflammations liable to be produced by colds or 
violent shocks? 

Prof. George Varnell, who believes caries of the roots 
of horses' teeth is usually caused by external violence, 
says: 

"Inflammation of the alveolo-dental periosteum 
would tend to this result (caries of the roots). AVhen 
the nutrition of any part of a tooth becomes arrested, 
decay is likely to follow. When caries begins from 
within, it is due to arrestation of nutrition, arising 
perhaps from disease of only a part of the central pulp 



NATURE BARRICADING DISEASE. 139 

of the tooth ; if from without, it will arise from the 
periodontal membrane where it meets the gum." 

Dr. John Tomes thus describes the conservative ac- 
tion of nature (barricading disease, as it were) when a 
tooth is affected with caries (-'Dental Physiology and 
Surgery"): 

"When a portion of dentine has become dead, it is 
circumscribed by the consolidation of the adjacent liv- 
ing tissue. The tubes, becoming filled up, are ren- 
dered solid, and the circulation is cut off from the dead 
mass. This consolidation does not go on gradually 
from without inward, keeping in advance of the decay, 
but occurs at intervals. It seems that successive por- 
tions of dentine lose their vitaUty, and that the contig- 
uous living portions become consolidated." 

Prof M. H. Bouley and Surgeon P. B. Ferguson are 
the joint authors of a memoir on horses' teeth, which 
fills thirty or more pages of " The Veterinarian " for 
1844. The substance of the part which relates to the 
pathology and dentistry of the teeth is as follows : * 

"'i. Anomalies in the Number of the Teetli. — Some- 
times, but very rarely, we meet with supernumerary 
grinders in the horse. The anomaly may be caused 
by the persistence of the temporary teeth, the develop- 
ment of abnormal teeth on one or both sides of the 
arcades (rows of teeth), and the cutting of a greater 

-■• The phraseology of Messrs. Bouley and Ferguson's memoir 
has been more or less changed and the niatter somewhat con- 
densed and rearranged. The surgeons' golden ideas deserve to 
be set forth in clearer and more forcible language than they re- 
ceive at their own hands, and i^. is believed that some improve- 
ment has been made. 



140 THE PATHOLOGY OF THE TEETH. 

number of permanent teeth than should naturally 
exist. In the latter case it is necessary to admit the 
existence of a greater number of dental bulbs than is 
normal. AYe saw some time ago, at the consultation 
of the Veterinary €ollege in Alfort/-' a horse which, to 
use the words of its owner, ' had a double row of teeth 
in the upper jaw.' 

'^Sometimes the supernumerary tooth is situated in 
one or the other jaw, in front of the normal range of 
grinders, without having a corresponding tooth in the 
opposite jaw ; at other times it is situated either within 
or without the arcade. The latter anomaly is caused 
more frequently by the deviation of a normal than by 
the addition of a supernumerary tooth. In the first 
instance it is not long before mastication is interfered 
with. The tooth, by its growth, which is not counter- 
acted by wear, finally reaches the opposite jaw, lacera- 
ting the mucous membrane and contusing and some- 
times fracturing the bone itself. In the second in- 
stance, the tooth, if within the arcade, is an obstacle 
to the tongue; if without, to the cheek. Besides these 
evil effects, supernumerary teeth cause irregularity in 
the arcades, and consequently prevent the exact appo- 
sition of the normal teeth. They interfere also with 
the action of the lower jaw. Hence irregularity in the 
friction and wear of the teeth follows, the result being 
that the performance of the all-important function of 
mastication is almost stopped. 

"^. Anomalies i)i the Form of the Arcades. — Th.e 
upper rows of grinder teeth form two curves, opposed 
by their concavities, while the lower rows form two 

* A city of France — Prof. Bouley's home. Surgeon Ferguson, 
an Englisliman, was attached to the Paris British Legation. 



DERANGEMEI!?'TS OF THE GRINDERS. 141 

nearly straight lines, which converge as they descend 
toward the symphysis of the clun. These (the curves 
and 'lines) may be, owing, in some cases, to congenital 
conformation, very irregular. Sometimes, in fact, the 
curves of the upper jaw are eSaced ; at other times, 
and most frequently, the lines of the lower jaw are 
incurvated within the upper arcades. The deformities 
may exist singly or together. The result is that, in 
the approach of the jaws, the relation is not identically 
established betvvTen the surfaces of friction, and the 
result of this, in turn, is an irregularity of wear and an 
abnormal development of the borders of the tables (the 
crowns of the teeth), within in the lower Jaw, without 
in the upper. 

".?. Exuberance of particular ^mrfs of the Dental 
Apparatus.— (A..) The upper grinders are wider than 
the lower, so that in order to cause friction in their 
entire thickness, a lateral movement of the lower jaw 
is required. Sometimes, perhaps because the move- 
ment is not effected throughout the entire limits of 
the segment of the circle, the outer borders of the 
upper teeth do not wear sufliciently, and therefore 
become elevated and sharp. At other times it is the 
inner borders of the lower teeth that project. In 
the former case the cheeks suffer; in the latter, the 
tongue. 

" In rare cases the tables, which present a normal 
inclination inverse in the two jaws, at length form 
planes very oblique. The obliquity is sometimes so 
great tliat the internal borders of the lower teeth arc 
very elevated, whVe the external is almost level with 
the gums. The inverse effect manifests itself at the 
upper jaw. The consequence is that the half-masti- 
cated food slips into the pouch of the cheek. 



142 THE PATHOLOGY OF THE TEETH. 

" There is in the museum of the College at Alfort a 
horse's head in which this deformity may be seen in 
its greatest degree. The tables of the teeth at the right 
side form ])lancs so much inclined that they close 
together like the blades of shears. As there was no 
friction to wear the teeth down, they grew to the hight 
of three inches. The fourth and fifth teeth of the 
right side of this rare anatomical specimen are absent. 
Perhaps they were carious. The rarefied and spongy 
tissue of the socket-bones indicate the seat of an alter- 
ation — probably caries — which was the point of depar- 
ture of the general tumefaction. The last toothy by 
its oblique direction toward the empty sockets, indi- 
cates that the loss of the teeth occurred during the life 
of the animal, some time perhaps prior to its death. 
The defect of the right side doubtless forced the ani- 
mal to use the left for the purposes of mastication. In 
such cases the teeth that do not wear grow till they 
reach their respective opposite jaws, even when those 
at the opposite side of the mouth are in exact con- 
tact, an anomaly never produced in the normal state. 
The function of mastication operates according to the 
obliquity of contact, and a parallelism is established 
by friction between the tables which normally would 
be superposed. 

" This appears to us to be the only interpretation of 
the facts, and we have observed two analogous exam- 
ples in living horses, but we did not think to ascertain 
whether the deformity of an entire arcade was owing 
to defect of a binder or to disease of the bone. The 
solution of the question would be an important acqui- 
sition to the science of dental pathology. 

" (B.) There is another kind of deformity of the 
arcades not very uncommon. The lower teeth wear 



"GUMMIITG IT." 143 

out more rapidly than the upper, the cause of which 
is perhaps owing to (he superiority of the latter in size 
and strength. The crown surface of the lower rows 
is slightly concave, the upper rows slightly convex. 
The result is that the lower center teeth are sometimes 
worn to their sockets, which renders the mastication 
of hard food impossible. At first, however, there is 
no interference with mastication, and it is usually only 
in old age that the defoi'mity reaches its worst stage. 
There is no remedy for the defect, hut its ^^rogress 
may he retarded hy the 2ise of soft food. * 

'*• (C.) Lack of regularity in the length of the rows 
becomes the cause, in horses a little advanced in age, 
of a peculiar deformity in the first upper and the last 
lower grinders. Generally the upper range passes that 
of the lower by some lines, the first upper grinder lap- 
ping over; but sometimes the case is the reverse, the 
last lower grinder projecting beyond the last upper. 
The projecting part of the tooth grows till it reaches 
the opposite jaw, when, unless it is filed or chiseled off, 
the most serious consequences will follow. 

" (D.) When a tooth is entirely deficient, the oppo- 
site tooth grows till it fills the void ; then, no remedy 
being applied, the work of destruction begins. If a 
tooth is only partly -deficient, no matter whether it be 
from fracture, caries, or arrestation of growth, it is 
gradually destroyed by the opposite tooth. AVhen it 
is the first upper grinder that is deficient, the first 
lower acts on the palatine vault like a battering-ram. 
*I have seen,' says Solle3^sel (1669), 'a mule that had a 
lower grinder of extreme length, the upper tooth being 
absent. The palate was pierced to the thickness of a 

* The italicized words are mine. — C. 



144 THE PATHOLOGY OF THE TEETH. 

finger, which caused the animal great difficulty when 
he drank/ 

•^^. Caries of the Teeth. — The grinder teeth of horses 
are more frequently afiected with a profound alter- 
ation of their substance than is generally believed. 
The disease is called Caries ; it may not, however, be 
strictly analogous to caries of tlie bones, for the bones 
are vascular, while the teeth have neither vessels nor 
nerves. Caries of tlie bones implies an active labor, in 
which the vascular apparatus plays an important jDart. 
It is a phenomenon of interstitial sup]3uration, under 
the influence of the inflammation which has set the 
capillary system of the organ in play. In explaining 
caries of the teeth, however, we cannot invoke the 
aid of inflammation and the modifications it induces 
in the tissues it attacks; nor can we say that inflam- 
mation implies an active circulatory movement, an 
afflux of liquid, an alteration, nervous deraugeraent, 
&c. If the teeth are living, the laws which govern 
their vitality are entirely unknown to us.* How, then, 
penetrate into the secrets of the alterations which they 
undergo, when the conditions of their normal existence 
are enveloped in obscurity? Neither is it possible to 
resolve the question as to the essence of the affection 
designated by the name of caries. Therefore we design 
to make known only the different modes of expression 
relative to it. 

"Caries usually attacks the dentine of the crown of 
the teeth, between two folds of enamel. The dentine 
becomes of a brownish or blackish color, and dissemi- 

'^' It sliould be borne in mind tbat the above views were enun- 
clnted more than a third of a contury ago. The gentlemen 
probably say too much. Compare with Dr. Hayes's views as 
recorded on page xxii. 



DEXTIIs'E DECAYED, EKAMEL SOFTENED. 145 

nates au ofFensive odor sui generis^ which perhaps is 
as much ovviug to the putrefactiou of the saliva iu the 
cavity as to the decomposition of the dentine. The 
decay progresses between tlie folds of enamel, and the 
latter substance, notwithstanding its great density, 
takes on the blackish tint of the dentine and becomes 
sufficiently softened to allow of its being cut by a sharp 
instrument. Sometimes even the planes of the enamel 
dissolve, and then the cubic mass of the tooth becomes 
so much decayed that it resembles a deep cavity, the 
parietes of which are formed by the planes of enamel 
laid bare by the caries. Sometimes caries attacks the 
tooth on one of its four side surfaces; at other times 
the root is attacked; but wherever its primitive seat 
may be, the blackish veins always extend into the den- 
tine, and thus isolate the plies of enamel. 

" Carious teeth rarely preserve either their form or 
volume. They become hypertrophied at their roots, 
but the effect does not manifest itself until the disease 
— having undermined all the layers of dentine in its 
course — has penetrated the root. "When the caries has 
penetrated to the socket, the alveolo-dental membrane 
becomes irritated by the contact of decayed matter, 
increases its secretion, and deposits a thick layer of 
osseous matter in the circumference of the root of the 
tooth, which concretes irregularly upon the normal 
layers. The deposition does not, however, always take 
place iu tlie circumference of the root, for in some 
cases it is only at isolated places that the secretion of 
the alveolo-dental membrane occurs. Then the root 
presents a succession of large osseous tubercles, which 
bar the tooth in, rendering its extraction very difficult. 
When the irritation has been from the first sufficiently 
active to cause suppurative inflammation, the normal 

r 



146 THE PATHOLOGY OF THE TEETH. 

S9cretion is suspended, and pus collects in the alveolar 
cavity, around the root, which then ceases to augment 
in volume. lo the former case, however, the root, 
augmented in volume, can no longer be contained in 
the cavity, the walls of which are expanded by its 
wedge-like action, which accounts for the extreme 
pain in the adjacent parts, and the particular altera- 
tions in the osseous tissues. The osseous tissue tume- 
fies, and suppuration is established in the interior of 
the socket; the membrane is partly destroyed, which 
leaves the bone bare and exposed to the maceration 
of pus and the irritating contact of the morbid matter 
that continually penetrates into the socket by the 
dental fistula; the bony tissue sphacelates upon the 
borders, where its substance is the most compact, and 
its spongy tissue, which forms the bottom of the cavity, 
soon becomes the seat of an interstitial suppuration — 
that is to say, in fact, of veritable caries. The swell- 
ing may now extend throughout the entire extent of 
the maxillary bone, and thus render mastication im- 
possible. 

" It may now be seen, an alteration of this nature 
being set in action, how the phenomena of the nutri- 
tion of bone may be modified in their direction to the 
point of producing osteosarcoma. 

'- Caries of the roots of any of the lower grinders may 
be complicated with lesions of the jaw, for the lower 
jaw is continuous in its entire extent. In the upper 
jaw the phenomena are in principle the same, but the 
contiguons nasal cavities and sinuses induce complica- 
tions the study of which is important. It is also im- 
portant to take into consideration the position of the 
diseased tooth, in order to appreciate the extent of the 
. lesions which a simple caries may produce. 



COMPLICATIOXS WITH iq-ERYES, SINUSES, ETC. 147 

''The two first upper grinder teeth are separated 
from the nasal cavities by a thin bone, wb.ich is easily 
eatcu througli. When caries attacks their roots, the 
inflammation extends itself to the membrane lining 
these cavities, aiid a perforation of the osseous partition 
may establish communication between tlie mouth and 
the nose. Under the influence of interstitial suppu- 
ration, the osseous membrane is destroyed to an enor- 
mous extent. The aliments pass through the dental 
fistula into the nose and are expelled by it along with 
the product of the morbid secretion of the pituitary 
membrane. 

"The third grinder is situated near the maxillary 
sinuses, from which the root is separated by a thin dia- 
phragm. It deserves to be specially noticed on account 
of an anatomical peculiarity, which renders caries of 
this tooth very much to he dreaded. We refer to the 
position of large fascias (bundles) of the superior maxil- 
lary brancli of the fifth ])air of nerves, which make 
their exit upon the face by the submaxillary foramen, 
and which are placed immediately over the root of this 
tooth. It is easy to imagine the pain that may follow 
nervous complications in caries of the roots of the 
third grinder. 

"The position of the fourth, fifth, and sixth grinder 
teeth, immediately holow the vast maxillary sinuses, 
from which their roots are separated by thin osseous 
partitions, gives to caries of these teeth, and to the 
complications which it induces, a special character, 
whicli demands that we should speak of it somowliat 
in detail. These teeth communicate with the sinuses 
as easily as the first and second do with the nose; but 
tlie case is far worse for the horse, there being so little 
outlet for the pus. 



148 THE PATHOLOGY OF THE TEETH. 

"When the disease has penetrated the roots, and 
has induced the usual inflammation, the thin parti- 
tions that separate them from the sinuses do not resist 
very long. Destroyed by the dilatory effort of the 
hypertrophied root and the influence of the caries, the 
altered matters of the mouth have free access into the 
sinuses. Under the influence of their contact, the 
membrane of the sinuses irritates, vascularizes, and 
thickens by a serous infiltration in the early stage. 
Then, the primitive cause of this modification contin- 
uing, the membrane hypertrophies somewhat, and in 
a short time, owing to its vascular system being richly 
developed by inflammation, large vegetations of the 
nature of polypi are elevated upon it. These, on ac- 
count of the incessant augmentation of their volume, 
fill the sinuses and cause a swelling of their walls. 

"When the membrane of the sinuses has become 
the seat of an abnormal vegetation, an abundant quan- 
tity of purulent matter is secreted, the more liquid 
l^art of which drains out through the conduits leading 
to the nasal cavities, while the more concrete part 
remains in the sinuses. It then, according as it loses 
its serosity, undergoes a transformation, and finally 
displays the aspect of cadaveric grease, which it also 
resembles in its repugnant odor. There is a great 
analogy between the disease that causes this particular 
lesion and that of glanders. 

^'Symptomatology. — The first symptom that indi- 
cates a derangement of the dental apparatus is a diffi- 
culty in mastication. The animal, excited by hunger, 
seizes the food with avidity. The motions of the lower 
jaw, however, are made with a sort of hesitation, and 
often only at one side. The imperfectly masticated 
hay, which on that account will not pass through the 



HUXGRY, BUT UXABLE TO EAT. 149 

narrow pharynx, is dropped into the manger in the 
form of cuds or flattened pellets. The nose is jolanged 
into the feed, over which the animal fumbles and nib- 
bles, but of which it eats little. 

"The insufficiency of nutrition soon produces a 
baneful effect on the whole economy. The coat tar- 
nishes, becoming dry and staring; the least exertion 
makes the animal sweat; it is heedless of the whip; 
the mucous membranes become discolored ; the pulse 
weakens, and cold infiltrations sometimes appear in 
the extremities. To see an animal thus suddenly 
transformed, one is apt to mistake the true cause and 
attribute it to the influence of some grave organic dis- 
turbance. 

" These symptoms are common to the different dis- 
eases and derangements of the dental ajDparatus, and 
are sufficient to lead to a positive diagnosis. The 
diagnosis, however, can only be precisely determined 
when the mouth shall have been examined, for by this 
means we perceive the particular signs of each of the 
alterations that opposes the function of mastication. 
The mouth may be kept open by a sjjeculum oris, or 
even by drawing out the free portion of the tongue, 
which should be held by the thumb and the third and 
fourth fingers, the index being placed between the 
inner side of the upper lip and the gum, at the space 
between the grinders and the tushes, while the other 
hand is left free to aid the inspection by taxis. 

''If the derangement be tlie result of an exuberance 
of a tooth, vicious inclination or projections of i\\Q 
tables, fractured teeth, swollen sockets, &c., the siglit 
is ordinarily sufficient to detect it, for the teeth are, 
besides, frequently soiled by the gro?nish remains of 
food at the affected part, and often even the cheek is 



150 THE PATHOLOGY OF THE TEETH. 

filled with an accumulation of malground food. The 
month should be cleaned with water, in order that the 
defect may bo more plainly seen ; if, however, on ac- 
count of its being situated far back in the mouth and 
the motions of the base of the tongue from side to side 
intercepting the view, its nature cannot be discov- 
ered with the eye, it will be necessary to resort to the 
sense of touch. The mouth being held open by the 
speculum oris, or some other firmly-fixed apparatus, 
the fingers should be passed rapidly within and without 
the arcades, but never on them, because of the danger 
of having them crushed : whatever may be the degree 
of forced dilatation of tlie mouth, there can never be 
much separation of the jaws in the region of the last 
grinders; besides the animal can lessen it by pressure. 

"When the buccal membrane has been excoriated 
by the contact of irregularly-worn teeth, the gums in- 
flamed, the jawbones contused, and the latter sphace- 
late or suppurate, there are some modifications of the 
general symptoms. The animal loses its appetite, 
becomes dull, ^ crest-fiillen,' and agitated with febrile 
disturbance, however little the heart of the inflamma- 
tion may be extended. The saliva, which dribbles 
from the mouth, is stringy, and, when mixed with 
pus, fetid; the mouth is hot and its membrane in- 
, jected ; there is a turgescence of the gum at the point 
of inflammation; a tumefaction of the bone, with a 
grayish tint at the point where it is denuded and about 
to exfoliate, or else fistulse abut into the heart of the 
suppuration in the spongy tissue of the jav/. 

''Particular Syriiptoms of Carles. — Caries of the 
grinder teeth is characterized by peculiar symptoms, 
some of which are common to the teeth in general, 
while others belong to some grinders in particular. 



CARIES DIFFERENT IX DIFFERENT TEETH. 151 

To give precision to the diagnosis, the position of the 
teeth should be taken into consideration. Besides the 
symptoms common to all disorders of the teeth, caries 
in general presents as diagnostic signs — 

*• 1, A fetor very remarkable and sin generis of the 
mouth, and of the saliva which humefies it. 

'''2. Dribbling of an abundant and stringy saliva 
froi^i the mouth. 

'' 3. Existence on one of the faces of the tooth, and 
principally upon its crown, either of a blackish spot or 
a large cavity of the same color, according to the ex- 
tent of the disease. 

'' 4. The extreme pain that the animal evinces when 
the tooth is struck. 

*^ If the disease is of long standing, and especially if 
it has arisen fi'om the side of the root, in addition to 
the foregoing modifications and complications, other 
and more special symptoms manifest themselves. The 
bone tumefies and the animal evinces pain when it is 
pressed by the fingers ; the gums are affected with tur- 
gescence, and bleed from the least contact; all the 
buccal mucous membrane reflects a red tint, and in 
the meantime fever sets in, manifesting itself by all 
its ordinary and general symptoms. 

^- Caries of the first and second upper grinders may, 
as already explained, be complicated with lesions of the 
nasal cavities. Then the pituitary membrane irritates 
and secretes abundant mucosities, but at one side only, 
v;ith which the fv)od l;ec;)m.'s mixed, giving it a green 
tint, but very diff^Tant from the secretions of glanders. 
The case is diifjrcnt, liuwever, in the complications 
induced by caries of the last grinders. In fact there 



152 THE PATHOLOGY OF THE TEETH. 

is such a close resemblance between the symptomatic 
expressions of the nose following caiies of these teeth 
and chronic glanders, that en-or and eoufnsion are 
common. It is therefore highly important to distin- 
guish these diseases, so essentially different in their 
causes and effects. 

" When the membrane lining the sinuses has become 
diseased, followed by the secretion of pus and polypus 
growths, a jettage is established at one side of the nose. 
It is white, lumpy, and abundant, and is augmented 
in quantity by exercise. The lymphatic ganglions be- 
come engorged and hard, but remain indolent, and 
generally roll under the finger. The zygomatic tables 
of the upper part of the superior maxillary and nasal 
bones swell at the region of the affected sinuses, and 
give a dull sound to percussion.* 

* Prof. Varnell says : "I am not aware that any animal suffers 
from diseases of tlie sinuses of the head to the same extent as 
the horse. The sinuses differ in size in different breeds, and in 
individual horses of the same breed. I need scarcely point out 
the necessity of bearing this fact in mind in forming diagnoses 
of obscure diseases in this region of the head. In certain cases 
it is not only important to ascertain whether the sinuses contain 
anything abnormal, but also the nature and extent of the mor- 
bific matter. Percu^Bion with the ends of the fingers is one 
mode of obtaining this information. Both sides of the head 
should be struck, and the sound produced in one part compared 
with that in another, and with what it is in health. I would 
recommend students to become familiar with these various 
sounds. They will be found to differ, according' to the magni- 
tude of the sinuses, in the same way that a large empty cask, 
when struck, will differ in sound from a small one. It will also 
be well to educate the ea.r to the character of the sounds pro- 
duced by iJKsrcussing the sinuses in differently formed heads. 
* * ^^' The sinuses, strictly speakinf>-, are air cavities, 
which communicate freely with each other, an:l by means of a 



DELICATE DIAGXOSTIC SIGNS. 153 

"At the first appearance of this group of symptoms 
one is apt to suspicion the existence of glanders, but a 
careful examination will prove it to be unfounded. On 
examining the nasi: cavity, the lining membrane will 
be seen to be smocth, polished, and uniformly rosy, 
with its normal fol icular openings, and on unfolding 
the superior wing of the nostril, the salient border of 
the cartilage presents a neat and polished surface, ivitli- 
out any little pimples or morbid tint. Xow, we know 
that in glanders, even of the sinuses, which is often 
unaccompanied by cankers or other ulcerations, it is 
in those places certain specific morbid signs may be 
recognized, which, although very superficial and with 
difficulty seen by the eye, are nevertheless of great 
value in the diagnosis. Such, for instance, are the 
peculiar aspect of the sahent border of the wing of the 
nostril, with its vivid red tint, the small superficial 
erosions of the fining membrane, entirely hidden under 
the fold of the cartilage, and those small granular pro- 
jections called tubercles. In the jettage from caries 
nothing of this kind exists. There is a marked diifer- 
ence in the odor too ; in caries the odor is exceedingly 
fetid, while in glanders it is almost null. 

" If, after this attentive examination, the surgeon is 
still in doubt as to the specific nature of the nasal dis- 

emall oponing, with the nasal passage also. This opening is 
situated at the supero-posterior part of the middle meatus, and 
is guarded by an imperfect valve, which, when pressed upon 
from within, either partially or wholly closes it. It may also 
be closed by the mucous membrane beinsr thickened by disease. 
Internally the sinusas are partially divided into compartments 
by thin osseous plates, and are lined by a slightly vascular mem- 
brane, which is continuous with that of the nasal passage, but 
is not so thick nor so vascular." 



154 THE PATHOLOGY OF THE TEETH. 

charge, it will disappear and give place to a -true diag- 
nosis when he has examined the month and has had 
time to weigh and compare all the facts in connection 
with the case. 

'•It is more especially relative to diseases of the teeth 
that u recognized the truth of the old maxim in sur- 
gery, SiiUatd causd^ tcdlitur cffectusr (The cause be- 
ing removedj the effect ceases.) 

For putting irregular teeth in order, the surgeons 
recommend the use of a coarse, six-inch file, with a 
handle from twenty to tv/enty-four inches long. How- 
ever, they say that in their day it was customary among 
the '"vulgar" to make the liorse clieio a rasp! The 
process, vvhich they describe, referring among other 
things to the difficulty of getting the rasp precisely 
opposite the projections, is too slow, as they admit, to 
be practicable ; besides it is about as difficult to com- 
pel a horso to chew as to compel him to drink. 

For the removal of siipernaraerary grinder teeth or 
the shortening of natural ones that have grown beyond 
the level of the other teeth, they recommend the use 
of a chisel and a hammer; two or three well-directed 
blows with the latter are usually ^sufficient to cut the 
largest tooth in two. The surgeon requires an assist- 
ant or " striker." In the case of the first grinder, the 
blow^s should be light, otherwise the tooth would be 
loosened in its socket. In tlie case of the last grinder, 
*'it is necessary for the operator to be perfectly master 
of the chisel at the moment of its being struck, for, in 
escaping, it might strike against the velum palati (soft 
palate) and cut it through." 

In performing these operations they prefer that the 
horse should be in a standing position, as when in a 



DEE]S;CHED WITH TOOTH-FKAGMEXTS. 155 

lying position there is danger of liis swallowing the 
migments of the teeth. If it is necessary, however, to 
cast the horse, they recommend that the head rest on 
the occiput, the operators being as expeditious as pos- 
sible, to prevent the" animal from swallowing the frag- 
ments. As the nose points up, the surgeon would 
have to be expeditious indeed in order to prevent the 
horse from being drenched, as it w^ere, with tooth- 
fragments. 

The surgeons next describe an interesting case of 
dental surgery, in the performance of which the bone- 
forceps were used to remove the tushes. They say: 

"It sometimes happens that the fleshy and bony 
structures of the mouth are not well proportioned, and 
when the anima,! is put to work evil consequences re- 
sult, especially if the tongue is too large for the space 
between the branches of the jaws. A remarkable case 
of this kind lately came under our observation in a 
horse owned by the Earl of Clonmel. The animal, a 
remarkably fine oi>e, was a very hard ^puller,' in conse- 
quence of the bit not coming in sufficient contact with 
the sensitive bars. The space between the tushes was 
too narrow for the tongue, which, after the animal had 
been ridden with restraint by a horse-breaker, was cut 
nearly through at each side. The consequence was the 
tongue became swollen to an enormous extent, and 
as the tushes increased the irritation, their removal 
became necessary. They were cut off to a level with 
the gums with the bone-forceps, the tongue was scari- 
fied and bathed v/ith a cold lotion, and the animal was 
fit for work at the end of a week. 

" Perhaps at first it may seem better practice in such 
cases to extract the tushes entirely. But when the 



156 THE PATHOLOGY OF THE TEETH, 

length and obliquity of their roots and the fact of their 
being situated in the weakest part of the jaw are con- 
sidered, it is plain that snch a procedure would in all 
probability be followed by the most serious results, 
SQch as fracture of the jaw, osteo-sarcoma, &c., the 
former having happened under our own observation.'' 

The surgeons recommend (as any intelligeut jiersou 
would) the removal of supernumerary or abnormal in- 
cisor teeth. When the tooth is without the normal 
range it interferes with the prehensile functiou of the 
lips; when within, it interferes with the tongue. The 
former, they say, may either be cut off with the bone- 
forceps or extracted. In the latter case, however, they 
prefer to cut them off, but admit that some teeth re- 
quire extraction, for which the use of the crank-forceps 
is recommended. 

The Treatment of Caries is the next subject consid- 
ered. " The only remedy for caries," the surgeons say, 
"in the great majonty of cases, is the extraction of the 
tooth. If we were called on to treat the disease at its 
beginning, cauterizing the black spot would check its 
progress ; but when the dental bulb has been attacked, 
the extraction of the tooth is the only remedy." 

The instrument recommended for extracting teeth 
is the forceps, and under ordinary circumstances, ihe, 
surgeons say, fracture of the jaws ought not to occur. 
They mention as useful instruments the key invented 
by M. Garengeot, the mouth-screw by M. Plasse, and 
the lever-forceps by Prof. Simonds, but say ; 

"Instances occur in which the carious tooth cannot 
be seized by any of these instruments. For example, 
when the last upper grinder is diseased, it is sometimes 



THE POWER OF THE TOKGtJE. 157 

impossible to dilate the mouth sufficiently to slide the 
instrument between it and the corresponding lower 
tooth. Besides, tlie tongue, however firmly it may be 
held outside the mouth, has still the power to displace 
the instrument by the energy of the undulatory move- 
ments at its base. Again, the back grinders, having 
ordinarily shorter bodies than the others, afford less 
hold for the instrument. In some cases they afford no 
hold at all, as their bodies are worn almost to a level 
with the gums. 

'^Lastly, in some cases the exostosis of the root of 
the tooth is so great that it is, as it were, wedged in 
the socket, and resists all efforts to extract it. What 
is to be done ? The disease may lead to grave local 
complications and dangerous general disorders. In 
such a case we would recommend trephining the dis- 
eased sinus and punching the tooth mto the mouth. 
This operation being very unusual, and the observance 
of some rules requisite for practicing it, we will con- 
sider it somewhat in detail. 

"If, as sometimes happens, the swelling over the 
sinus is indistinct, it would be wtII to be guided by a 
prepared head, in order to apply the trephine in the 
exact place, wdiich is above the diseased root. A large 
V or crucial incision should be mad-e, and the trephine 
manipulated till the sinus is laid open. The opening 
should be extensive rather than confined; it is more 
convenient to apply upon the parietes of the sinuses 
three crowns of the trephine, tangent reciprocally at 
their circumferences; then, by the aid of a sharp in- 
strument and a small hammer, the angles may be re- 
moved. 

"As soon as the mucous membrane of the cavity has 
been laid bare, the change it has undergone may be 



158 THE PATHOLOGY OF THE TEETH. 

seen, and also the vegetations springing from it. At 
the bottom of tlie sinus, toward the alveolar border of 
the jaw, among the vegetations, is a hard, granulated, 
dry surface, resistant to the touch, of a grayish tint, 
and analogous to sphacelated bone. This is the sum- 
mit of the root of the tooth. 

" The surgeon then arms himself with an iron punch, 
rounded at the point, which he applies to the root in 
the sinus, and having further separated the jaws by a 
few turns of the speculum oris, commands an assistant 
to strike sJiort, hard blows, tlie surgeon looking at the 
tooth to see the effect of each blow. Usually the tooth 
soon gives way, and falls into the mouth generally in 
two fragments, according to the direction of the caries. 
Sometimes, however, from the length of the tooth, it 
cannot be punched entirely into the mouth, being 
stopped by the opposite' lov/er tooth ; but it may be 
wrenched out with a pair of long pincers, the handles 
of which should be separated to increase the power of 
the operator. When the operation is terminated, the 
vegetations of tiie mucous membrane, as far as they 
can be ]*eached, must be excised. To stop the hem- 
orrhage, and to modify the state of the mem^brane, 
pledgets of tow, moistened with a diluted solution of 
nitric acid, or some other caustic, should be applied. 

*'It is really extraordinary with what rapidity the 
structural breaches resulting from this operation are 
restored by the reparatory efforts of the organic econ- 
omy. The first time we performed the operation we 
doubted the animal's recovery. The sinuses, laid open 
by a breach nearly two inches and a half in diameter, 
communicated with the mouth by an enormous open- 
ing, the root of the tooth having acquired nearly three 
times its normal volume. The lining membrane of 



' TREATMENT AFTER TIIEPHIKING. 159 

the maxillary sinuses, and the frontal also, had suffered 
the transformation already described to its greatest 
degree. And, linally, it required efforts almost beyond 
belief to loosen the tooth and force it from its socket. 
Still the animal made a good recovery. 

*' The treatment following the operation should he ^ 
a? follows: Assiduous attention to cleanliness is nec- 
essary from the first. On the first day the animal 
should be deprived of all solid or fibrous food; in fact, 
a little thin gruel is all it requires, and the mouth 
should be gargled with an acidulated fluid even after 
its use. The fluid may be applied with an ordinary 
syringe. Bleeding is often required, the quantity of 
blood to be abstracted depending on the energy of the 
reaction following the operation. 

" On the day after the operation the dressing should 
be raised. The interior of the sinus, cauterized with 
nitric acid, reflects a blackish tint. The odor is repug- 
nant, and there are generally some remains of putrid 
alimentary matters, mixed with clots of blood, in the 
sinus. Detergents, such as Lebarraque's -chlorinated 
solution of soda, mixed with a gentian wine, should be 
injected into tlie sinus and the mouth cleaned with 
acid gargles ; a firm pledget of chlorinated tow should 
be introduced into the socket, to prevent anything 
passing from the mouth to the sinus. The regimen 
should consist of gruel only, the gargles to be used 
often during the day. 

" On the second day the borders of the sinus will be 
a little swollen. Eeparatory work has begun in the 
cauterized membrane; the eschars detach themselves, 
exposing a rosy surface of fiivorable aspect to the view. 
The odor is less repugnant. Continue the aromatic 
detergent injections, the same food, with the addition 



160 THE PATHOLOGY OF THE TEETH. 

of a little bran, and gargle often. As suppuration be- 
gins to establish itself, the dressings should be renewed 
two or three times during the twenty-four hours. 

" It is not our intention to indicate the progress of 
the wound and the attention it demands from day to 
day. The tumefied bones and other structures in the 
region of the wound 2:)roportionally lessen, and the 
membrane of the sinus takes on a uniformly rosy tint 
and the glistening, humid aspect proper to a mucous 
membrane. The nasal flux finally ceases, the matter 
that may be secreted finding an outlet through the 
alveolus into the mouth. The opening made by the 
trephine contracts itself by degrees, but in extreme 
cases, like the one we have described, it is never suffi- 
cient to entirely repair the structures cut away. It 
may be hidden, however, by a leather or metallic j)late, 
attached to the check of the bridle." 

The surgeons claim that the resort to this severe 
mode of extracting teeth is justified by the success of 
the operation and its concomitant results, namely, the 
advantage of injecting the sinuses and preventing un- 
healthy secretions by them, and the stopping of the 
discharge from the nose, which had aroused suspicion 
of glanders. They further sa}" — and a better argument 
in favor of veterinary dentistry could not well be ad- 
vanced — that they believe glanders is often caused by 
the neglect of diseased teeth, and "that the modus 
operandi of its production in such cases may be ex- 
plained on the ground of the absorption of pus by the 
constitution." 

Of trephining the sinuses they further say; 

"We have treated many cases of caries successfully 
by simply trephining the frontal and maxillary sinuses 



CARIES OF THE SOCKET BONES. 161 

and injecting detergents; but in a far greater number 
the treatment has been unsuccessful.* Yet we believe 
that if, in addition to trephining, the teeth had been 
extracted, and a communication established between 
the sinus and the mouth, the results would have been 
more favorable. 

"Monsieur Delafond, in his memoir on the evulsion 
of the teeth, publislied in 1831, says the operation of 
trephining is only practicable in the case ot the three 
first grinders, it being necessary in the case of the three 
last to make an incision through the zygomatico-maxil- 
laris muscle and the nervous plexus which is formed 
on it. We, on the contrary, claim that the fifth pair 
of nerves will be injured in operating on the three first 
teeth, but that there will be little injury to the muscle 
in the case of the three last." 

The memoir concludes as follows: 

^'Caries Attaclcing the Maxillary Bone after the Ex- 
traction of the Teeth. — When caries of a tooth has in- 
duced consecutively interstitial suppuration of the 
spongy tissue of the socket, it is possible that, even 
after the extraction of the tooth, the disease may at- 
tack the bone. Then, more than ever, may we dread 
the tumefaction of the tissues and sarcomatous altera- 
tions, which are ordinarily the result of persistent sup- 
puration in the areolge of the spongy substance of the 
bones. To prevent these dangerous consequences, the 
socket should be cauterized with the actual cautery, 

* " Sinuses that may have formed by the matter from ab- 
scesses in the alveohir processes eatin<i; its way through the wall 
of the alveolus, and wliieli may open either on some part of the 
face or within the mouth, are seldom treated with the success 
one could desire." — Prof. George Varncll. 



162 THE PATHOLOGY OF THE TEETH. 

and, if it is practicable, a counter opening by trephin- 
ing should be made. In some cases in our practice 
this mode of treatment produced the most satisfactory 
results. If, however, on account of the circumstances 
of the case, the actual cautery cannot be used, a strong 
solution of argenti nitras, applied with pledgets of tow 
or lint, may be substituted. 

" Complications of Operations on tlic Mouth. — One of 
the most ordinary and serious complications of opera- 
tions on the mouth is the excoriation of the ^bars^ by 
the friction of the speculum oris. The denuded bone 
often exfoliates, rendering the horse unfit for work for 
a month or more. The evil may be avoided by envel- 
oping the transverse bars of the speculum with tow or 
some other elastic material, and by being expeditious 
in operating. The hemorrhage, which is never abun- 
dant enough to be serious, may be checked by pledgets 
of tow, wet with a solution of either nitric or sulphuric 
acid. 

''^Regimen. — The regimen in extreme cases of caries 
has already been indicated in the account of the case 
of trephining for caries and exostosis of the root of a 
grinder. In addition to well-boiled gruel, mixed or 
unmixed with bran, carrots and similar food will be 
found beneficial."* 

^' As horses with defective, diseased, or worn-out teeth require 
soft or ground food, a few extracts from tlie article on " Food " 
in Prof. Youatt's work entitled " Tlie Horse " (p. 132) and otlier 
sources will not be out of place here : " Oatmeal gruel consti- 
tutes one of the most important articles of diet for the sick 
horse. Few grooms make good p:ruel. It is either not boiled 
long enough, or a sufficient quantity is not usxl. The propor- 
tions should be a pound of meal to a ,ffallon of v/ater. It should 
be constantly stirred till it boils, and for five minutes afterward. 
Carrots, according to Stewart's ' Stable Economy,' are a good 



PROF. VAR NELL'S VIEWS. 1G3 

Prof. George Varnell, of the Royal Veterinary Col- 
lege of Loudon, the aathor of a series- of articles "On 

substitute for grass, and in sick or idle horses render corn un- 
uecossary. They improv^e the state of the skin. At first they 
are slightly diuretic and laxative, but the effect lessens with use. 
Half a bushel is a large daily allowance. Swedish turnips and 
raw potatoes are useful foods. Raw potatoes, sliced and mixed 
with chaff, may be given t j advantage, but it is better to boil or 
steam them, as purging rarely ensues. For horses recovering 
from sickness, barley in the form of malt is serviceable as tempt- 
ing the appetite and recruiting the strength. It is best given 
in mashes, water somewhat below the boiling heat being poured 
upon it, and the vessel kept covere:! for half an hour. Rye is 
used in Germany, but generally cooked as bread, which is made 
from the whole flour and bran. It is not unusual in traveling 
through some parts of Germany and Holland to see the postil- 
ions help themselves and their horses from the same loaf. In 
some northern countries peameal is frequently used, not only as 
food, but as a remedy for diabetes. Linseed, raw, ground, or 
boiled, is sometimes given to sick horses. Half a y>int may be 
mixed with the feed every niglit. It is supposed to be useful in 
cases of catarrh. It is very useful for a cough, but it is too 
nutritious for a fever. For a cough it should be boiled and 
given in a bran mash, to which two or three ounces of coarse 
sugar may be added. Tares, cut after the pods are formed, but 
some time before the seeds are ripe, lucern, and sainfoin are 
useful foods. Of the former the variety known as vicia sativa 
is th.e best." 

On page 511 Prof. Youatt says '' some greedy horses habitu- 
ally sv/allow their food without properly grinding it." As a 
remedy he recommends that chaff be mixed with the corn, cats, 
or beans, which, being too hard and sliarp to be swallowed with- 
out chewing, compels the horse to mnsticate his food. He says : 
" Chaff may bo composed of equal quantities of clover or meadow 
hay and wheaten, oaten, or barley s'raw, cut in pieces of a quar- 
ter or a half an inch in length, and mixed well together. The 
allowance of corn, oats, or beans is added afterward, and mixed 
with the chaff. Many farmers very properly bruise the oats and 
beans. The whole oat is apt to slip out of the chaff and be lest. 



164 THE PATHOLOGY OF THE TEETH. 

Some of the Diseases Affecting the Facial Region of 
the Horse's Head" ("Veterinarian," 1866-67), and 
other productions, has made the disorders of horses' 
teeth a study, and has aided somewhat in clearing the 
"mystery" that Surgeon Gowing believes will "to a 
certain extent always remain," for he has succeeded in 
casting some light on the aetiology of a tooth's greatest 
enemy — caries. His suggestion as to plugging teeth 
with gutta-percha is novel, and in some cases might 
be practicable. However, would not cement, which 
gives such perfect satisfaction in human dentistry, be 
preferable ? It is not expensive, and can be as readily 
introduced into a cavity as gutta-percha; besides, as 
the cavity must first be thoroughly cleaned (no matter 
which is used), its use in the end might save time and 
the tooth be much longer preserved. A horse's tooth 
that can be got at conveniently, ought to be filled as 
easily and, in decay of its neck, perhaps a 5 successfully 
as a human tooth. Prof. Varnell's views are in sub- 
stance as follows ("Veterinarian," 1867): 

" Caries of the -fangs of the grinder teeth is rare and 
generally very difficult to account for. I think that, 
in the majority of cases, it depends upon external vio- 

For old horses, and for those with defective teeth, chaff is pecu- 
liarly useful, and for both classes the i^rain should be broken as 
well as the fodder. The proportions are eight pounds of oats 
and two of beans to twenty of chaff." 

ConcerninfT swallowing without grinding Prof. Youatt further 
says : " In cases of this kind the teeth should be examined. 
Some of them may be unduly lengthened, particularly the first 
of the grinders, or their ragged edges may wound the cheek. In 
the former case the hors;=^ cannot properly m^.sticate his food ; 
in the latter he will not, for horses, as too often occurs in sore 
throat, would rather starve than put themselves to much pain." 



THE ALYEOLO-DEXTAL PERIOSTEUM. 165 

lence, although we are not always able to trace it to 
such a cause. Inflammation of the alveolo-dental peri- 
osteum, especially where it surrounds the fang or fangs 
of a tooth, would tend to this result. Other causes 
may produce the same effect. Indeed, Avhenever or 
however effected, wiien the nutrition of any part of a 
tooth ceases, decay is Ukely to foll*Ow. V\^hen caries 
beirins from within, it is due to cessation of nutrition, 
arising perhaps from disease of only a part of the cen- 
tral pulp of the tooth. If from without, it arises from 
the periodontal membrane where it meets the gum. 

" Caries of the cervix (neck) of the tooth is much 
more common than it is in the fang ; still it does not 
occur in more than one horse in five hundred. The 
question will naturally be asked, To what does this 
tendency to decay belong ? Under such circumstances 
are we not forced to the conclusion that it must de- 
pend either upon a defective structure of the tooth, or 
that the dentine, enamel, and cement are dispropor- 
tionately developed, or that one of them is defective in 
its parts ? Another and perhaps the most frequent 
predisposing cause of caries of the neck of the grinder 
teeth is that food becomes impacted betw^een them. 
Its decomposition may not only affect the teeth, but 
the alveolar processes also." 

The professor believes that caries of the crown of a 
tooth is generally caused by the horse biting on a stone 
or piece of metal during mastication. If the stone is 
lodged in the cavity of the infundibulum, the pulp of 
the°tooth may be injured, for, to use the professor's 
words, '' the thickness of the tooth between the upper 
part of the pulp-cavity and the bottom of the deepest 
infundibula is not very great." 



166 THE PATHOLOGY OF THE TEETH. 

Of the treatment of caries of the necks and crowns 
of grmder teeth, the professor says: 

'^ As I am riot avfaro of any treatment by which the 
decaying' process can be stopped, I would as an experi- 
ment in suitable cases — that is, in those in which the 
diseased part may 'be got at — phig tlie tooth with gutta- 
percha, having first thoroughly cleaned the cavity. If 
?ae plug can be retained in its place, some benefit may 
be derived from its use. Believing, however, that the 
decomposition of food impacted between the grinder 
teeth is one of the exciting causes of their decay, I 
would advise that it be now and then removed. It 
would not only prevent decay, but in cases where decay 
had already begun, would to some extent check its pro- 
gress. Indeed, I think the health of the horse would 
in many cases be improved by the adoption of such a 
plan." 

Yfliile the professor recommends gutta-percha plugs 
for the crowns of slightly decayed grinders, he says 
that, compared v/ith those of the necks, they are "less 
likely to be of even a slight benefit, inasmuch as the 
plug would be removed by attrition." Where the in- 
terior of the grinder is destroyed by disease, and the 
usual longitudinal fracture has occurred, he extracts 
the tooth with the forceps. While, as a rule, the tooth 
fractures longitudinally, the corners, he says, are some- 
times broken off. * 

In commenting on the diseases of the alveolar pro- 
cesses. Prof. Varnell says: 

"The causes which give rise to this condition of the 
maxillary bones are not easy to define. That a horse 
so affected is from certain peculiarities predisposed to 



DISEASE OF ALVEOLAR PROCESSES. 167 

it, there can be no donbt. For example, tlie teeth be- 
ing placed at a distance from eacli other, thereby allow- 
ing the food to lodge between them, mnst be looked 
npon as a predisposing cause. A strumous diathesis, 
which I believe to be more common in the horse than 
is usually supposed, must also be regarded as a predis- 
joosing cause. The particles of food which become 
impacted in these unusually wide interdental spaces, 
after a time decompose and give rise to fetid com- 
pounds, which act prejudicially on the parts they are in 
contact with. The membrane which covers the gums, 
and also that which lines the alveoli and is reflected 
on the fangs of the teeth, becomes inflamed. The 
inflammation will extend to the bone, the blood-vessels 
of which will become enlarged, as will also the Haver- 
sian canals in which they ramify. The osseous larainaB 
surrounding these canals v/ill be partially absorbed, 
and to some extent separated from each other, and the 
enlarged spaces thus produced will be filled with in- 
flammatory exudation. Hence the soft, spongy state 
of the gums and their tendency to bleed from slight 
causes ; hence also the looseness of the teeth in the 
alveoli." 

Of the deformity called Parrot- 3Io2{tJi, and irregular- 
ities of the incisor teeth, Prof. Varnell says: 

" This deformity consists in the upper incisor teeth 
projecting in front of and overhanging the lower ones 
to the extent in some instances of an inch and a half. 
The deformity resembles the upper bill of the parrot, 
which projects over the lower ; hence the name. The 
lower incisors, from not being worn off by attrition, 
may become so long that the roof of the mouth is seri- 
ously injured. The deformity is generally associated 



168 tHE PATHOLOGY OF THE TEETH. 

with an irregular position of the upper grinders rela- 
tively with the lower. 

'' Sometimes the horse, when at pasture, is unahle to 
take a sufficient quantity of food to keep himself in 
condition, and consequently he is considered legally 
unsound. But if fed from the manger he experiences 
little trouble in collecting his food; nor will his ability 
to masticate it be interfered with, except perhaps in 
old age. 

" Treatment. — The treatment can only be palliative. 
If the roof of the mouth should become diseased and 
mastication impaired, the only remedy is to reduce the 
length of the lower incisors. The instrument generally 
used is a file or a rasp, but the process is so tedious and 
slow that it is seldom that much good is done. If the 
sliding-chisel could be brought to bear on them, their 
length could be readily reduced. Talking on the sub- 
ject with my friend, Surgeon Gowing, he suggested a 
modification of this instrument which, I think, would 
answer very well. 

"Irregularities of the incisor teeth, both with refer- 
ence to their position and number, are even.more com- 
mon than in the grinders, but they seldom cause actual 
disease." 

Prof. William Williams, like Prof. Yarn ell, has per- 
formed his part in elucidating the subject of caries of 
the teeth, and he has also illustrated the transmission 
of vitality to them from the outside — through the me- 
dium of the cement— after it has ceased to flow through 
the pulp on the inside, the pulp having become con- 
verted into dentine. It appears that anything that 
disturbs the equilibrium of this flow of vitality, which 
is the secret of the growth of the teeth throughout 



CEMEXT FILLING THE PULP'S OFFICE. 169 

life, may cause caries. Prof. Williams says (" Princi- 
ples and Practice of Veterinary Surgery," p. 470) : 

*' Caries, dental gangi-ene, or decay, is almost exclu- 
sively confined to the grinder teeth— although I have 
seen the incisors in that condition— and may begin 
primarily in the fang, neck, or crown of the tooth. 

"' Caries of the fang arises from inflammation of the 
pulp, and may be caused by a constitutional predispo- 
sition or external injury. Inflammation of the pulp, 
however, does not always cause caries. I have several 
cases on record where the fangs were enlarged from 
periodontal deposit, with abscesses surrounding the 
fangs, without caries. Caries beginning at the fangs 
may be due to the obliteration of the pulp-cavity at 
an age when the vitality of the tooth depends upon 
the integrity of the pulp. I need scarcely remind the 
professional reader that the integrity of the teeth de- 
pends upon a due supply, hoth as to quantity and 
quality, of nutritive materials. 

*'Ori the fangs of a recently cut tooth but little 
cement is met with compared with that which exists 
in old teeth. As age advances the cement increases, 
and the tooth grows from the outside. In man it is 
generally agreed that after a given time the dentine 
ceases to be produced, and that the pulp is converted 
into osteodentine. In the horse the pulp-cavity be- 
comes obliterated gradually by the pulp continuing to 
form dentine, the pulp simply giving way to its own 
product, which ultimately occupies its place and fills 
its cavity. In proportion as the pulp diminishes the 
supply of nutriment is lessened, .until at length it is 
entirely cut off from the interior; to provide for the 
vitality of the tooth the cement increases in quantity 
8 



170 THE PATHOLOGY OF THE TEETH. 

on the fang, and at the expense of the perfectly formed 
dentine lying in immediate contact with its inner sur- 
face. That is to say, this layer of dentine is converted 
into cement by the dentinal laconge nndergoing dila- 
tation and becoming identical with the hollow spaces 
or cells of the cement. The tooth now draws its nour- 
ishment from the blood-vessels of the socket, and thus 
continues, long after the obliteration of its pul]3-cavity, 
to perform its part in the living organism. 

'•This is the natural condition of old teeth. But 
when the pulp-cavity is obliterated at an early age, by 
a too rapid formation of dentine, and consequent ob- 
literation of the pulp when the cement is not yet suffi- 
ciently developed to supply nourishment to the whole 
tooth, caries must be the result. Many cases of caries 
that have come nnder my observation have resulted 
from this cause, and very often the disease is confined 
to that part of the cement that dips with the enamel 
into the interior of the tooth, splitting it into several 
longitudinal fragments. 

"Caries of the neck of the tooth is seen in those 
iiorses whose teeth are wide apart, and is caused by 
the food remaining in the interspaces, and by decora- 
position exciting inflammation in the periodontal 
membrane. Caries of the neck is very commonly met 
with in the teeth of dogs, sometimes causing abscesses 
in the cheek. 

^'Caries beginning at the crown is due to a portion 
of the dentine losing vitality and the power of resist- 
ing the chemical action of the fluids of the mouth. A 
portion of the enamel of the crown may be fractured 
by biting a stone or piece of metal contained in the 
food. Mere fracture of the enamel, however, is insuffi- 
cient of itself to lead to caries of the teeth in the lower 



SIFTING THE FEED. 171 

animals, for it is a substance that is gradually worn 
off by mastication ; but the violence which has caused 
fracture of the enamel, may at the same time have 
caused such an amount of injury to the dentine that 
it dies, and progressively becomes decomposed. In 
man it seems there should be death of the dentine and 
acidity of the oral fluids before caries can take place, 
test-paper applied to a carious tooth invariably show- 
ing the j^resence of free acid, and a very small perfora- 
tion in the enamel may coexist with a considerable 
amount of disease in the dentine." 

Surgeon T. W. G owing, of London, a well-known 
inventor of dental instruments (veterinary), in an 
'' Essay on the Diseases of the Teeth of the Horse," 
which was printed in "The Veterinarian" for 1851 
(p. G32), in substance says: 

"I am aware that the cause of disease of the teeth 
must to a certain extent always remain a mystery; yet 
from observation and reflection we may be able to de- 
duce conclusions which practice will confirm. 

"Let us consider the two classes of horses that we 
are principally called upon to attend, namely, the cart 
or draft-horse, and the hack or carriage-horse. So far 
as my observations have led me, the latter class are 
less liable to diseases of the teeth than those of a 
coarser breed. Now, may not this be caused by the 
better care they receive in the stable? The good and 
efficient groom regularly sifts the provender previous 
to feeding his horses, and thus rids it of stones, glass, 
&c. Tlie cart-horse and the machine-horse of our 
London omnibus proprietors, not receiving this atten- 
tion, are more subject to diseases of the teeth. Be- 
sides, it is a common practice with carters to sprinkle 



172 THE PATHOLOGY OF THE TEETH. 

the provender with sulphuric acid, and we well know 
how acids affect the teeth. If such practices be al- 
lowed, diseases of the teeth may be readily accounted 
for. 

" The teeth being lowly organized, soon lose their 
power of self-preservation. Tney are affected by the 
general health of the animal. Should the function of 
the stomach or alimentary track be deranged, the teeth 
— from the general health of the animal being inter- 
fered with, and from the local functional derangement 
— of all parts of the body, are the first to suffer or de- 
cay. Absorption of the gums, which may be caused 
by the decayed food that lodges between the grinders, 
is often followed by decay of the cement, which, being 
the most exterior as well as the most highly organized 
of the three substances composing the teeth, is the 
first to yield." 

After describing the usual symptoms of diseased 
teeth. Surgeon Gowing asks : 

" Who that has observed these symptoms, can hesi- 
tate for a moment to acknowledge that the animal is 
suffering pain, which, if we were to say arose from 
toothache, would not be beheved by our employers?" 

Prof. W. Youatt says in substance ("The Horse," 
p. 230) : 

" Of the diseases of the teeth we know little. Cari- 
ous teeth are occasionally seen. They not only render 
mastication difficult, but they sometimes impart a fetid 
odor to the food, and the horse acquires a distaste for 
aliment altogether. Carious teeth should be extracted 
as soon as their real state is known, for the disease is 
often communicated to the contiguous teeth and to 



FUXGUS H^MATODES. 173 

the jaw also. Dreadful cases of 'fungus hsematodes' 
have arisen from the irritation of caries. 

" Every horse that gets thin or out of condition, 
without fever or other apparent cause, should have his 
teeth and mouth examined, especially if, without any 
indication of sore throat, he * quids' his food; or if he 
liolds his head to one side while he eats, in order to 
get the food between the outer edges of his teeth. The 
cause is irregular teeth. Such a horse is materially 
lessened in value and is to all intents and purposes 
unsound, for although the teeth may be carefully sawn 
down, they will project again at no great length of 
time. Ahorse cannot be in full possession of his nat- 
ural powers without perfect nutrition, and nutrition 
is rendered imperfect by any defect in mastication." 

Prof. R. Owen, in his work entitled "A History of 
British Fossil Mammals and Birds " (pp. 388-0), gives 
an account of a diseased fossil horse's tooth which he 
found at Cromer. He says he is " induced to cite one 
of the curious examples of disease in an extinct animal 
from the rarity of its occurrence in the tissue which is 
the subject of it." The facts of this rare case are as 
follows: 

" One of the Cromer fossil teeth, from the lower jaw, 
with a grinding surface measuring one inch five lines 
in long (antero-posterior) diameter, and eight lines in 
short (transverse) diameter, presented a swelling of 
one lobe, near the base of the implanted part of tlie 
tooth. To ascertain the nature and cause of this en- 
largement, I divided it transversely, and exposed a 
nearly spherical cavity, large enough to contain a 
pistol-ball, with a smooth inner surface. The parietes 
of this cavity, composed of dentine and enamel of the 



174 THE PATHOLOGY OF THE TEETH. 

natural structure, were from one to two lines and a 
half thick, and were entire and imperforate. The 
water percolating the stratum in which this tooth 
had lain, had found access to the cavity through the 
porous texture of its walls, and had deposited on its 
interior a thin ferruginous crust; but the cavity had 
evidently been the result of some inflammatory and 
ulcerative process in the original formative pulp of 
the tooth, very analogous to the disease called 'spina 
ventosa' in bone." 



CHAPTER IX. 

THE DENTISTRY OF THE TEETH. 

Reports of Cases Treated by Various Surgeons. — Gutta-Percha 
as a Filling for Trephined Sinuses. — Teetli Pressing against 
the Palate. — Passing a Probe through a Decayed Tooth. — 
Death of a Horse from Swallowing a Diseased Tooth. 

Horsemen, farmers, and otlier practical men will 
find much useful information in the present chapter, 
for it is based on the experiences of Veterinary Sur- 
geons, whose reports appear in the various volumes of 
*'The Veterinarian" (printed monthly in London), 
and to which I am so much indebted for other useful 
information. It is probably not too much to say that 
the more generally the chapter is read the fewer horses 
will be killed in the future for ha\ang decayed teeth, 
accompanied with a discharge from the nostril. 

In ^'The Veterinarian" for 1856 (p. 437) Surgeon J. 
Horsburgh reports the following interesting case, en- 
titled "Chronic IS'asal Gleet produced by a Diseased 
Tooth:" 

'^ About twelve months a^o I was consulted about 
the case of a mare with a discharge from the near nos- 
tril. " She had been under treatment for eighteen 
months, and the superior maxillary sinus had been 
opened with the trephine. The discharge, however, 
continued to flow^ both from the nostril and the 



176 THE DEIS'TISTRY OF THE TEETH. 

wound, notwithstanding the trephining had been per- 
formed a year before I saw the animal. 

" The defluction had an offensive smell, and the sub- 
maxillary gland was enlarged, causing sus])icion of 
glanders. The opening had been made a little too 
high, so that the central instead of the superior part 
of the sinus was perforated. I found that the whole 
mischief was caused by a dise^ised tooth. With the 
assistance of a smith I removed the tooth, which was 
split up its middle and considerably decayed- It was 
more than two inches long, and was bent forward to- 
ward the cheek. The odor was most offensive. I then 
opened the frontal and maxillary sinuses, both of 
which were filled with fetid pus. The wounds were 
first treated with a weak solution of chloride of lime, 
and subsequently with an ordinary astringent lotion. 
In addition to the local treatment, I administered the 
diniodide of copper. 

"After a considerable time the wounds were allowed 
to heal, and the mare appeared much better. But very 
shortly the discharge began to flow again worse than 
ever, and the smell was almost intolerable. Deter- 
mined, if possible, to make a cure of the case, I cut 
into the sinus again with the skull-saw, taking out a 
triangular piece of bone about two inches long by one 
inch and a half broad. At the upper part of the 
cavity I found some masticated food in a state of de- 
composition. It had passed through the alveolus into 
the sinus. Fractured bones were removed, and the 
opening being extended through into the nostril, a 
small instrument could be passed dov/n it into the 
mouth. A weak nitric acid lotion was used to induce 
fresh inflammatory action, and, if possible, to fill up, 
by an effusion of lymph, the passage through which 



CURED INSTEAD OF KILLED. 177 

the food was pressed upward from the mouth into the 
cavity. The external wound was dressed with an 
ordinary heahng lotion, and tow Avas put into it daily, 
and pressed downward to the mouth. A little Ulster 
liniment was also occasionally applied. 

^'Before operating, the frontal sinus on the affected 
side was considerably more bnlging than the other. It 
is now reduced, and the wound has healed. The dis- 
charge from the nose has stopped, and there is no 
smell. Thus, after about two years and a half of 
treatment, this mare, now only five years old, is able 
to resume her work, and has every appearance of being 
likely to remain well. 

" Had I not been able to effect a cure by the closing 
of the passage into tlie mouth, I would have tried 
filling it with gutta-percha. If a discharge w^re to 
take place again in this case, it would no doubt depend 
on the existence of a small aperture, and, under such 
circumstances, I should not hesitate to again cut into 
the sinus and endeavor to close the opening in the 
bone with gutta-percha, or some similar substance.'^ 

Surgeon H. Surmon, in an article ^^ On the Extrac- 
tion of Projecting Teeth," tells how he saved a horse 
that had been ordered killed by its owner ("Veterina- 
rian," vol. ii, p. 2b): 

" Last year a neighbor of mine had a horse which 
had been losing flesh for some time, and his appetite 
Avas gradually diminishing. When I first examined 
the horse I saw no appearance of disease that could 
affect his appetite, and looking at his mouth I per- 
ceived no laceration of the cheeks or other injury. 
The horse grew worse, became almost a skeleton, and 
its owner ordered that it be killed. Beinir informed 



178 THE DEITTISTRY OF THE TEETH. 

of the fact, I expressed a wish to examine his mouth 
once more. I accordingly put a balling-iron into his 
mouth and introduced my hand, and at the extremity 
of the grinders I found two teeth, one on each side of 
the lower jaw, which had grown long enough to press 
into the roof of the mouth, and thus prevented the 
animal from eating. I endeavored to extract these 
teeth with an instrument similar to that used for the 
human teeth, but without effect, as it could not be 
got on them. I then contrived an instrument v/hich 
v.as very simple. When it was passed up the mouth, 
the tooth became fixed between the divided end of the 
iron ; the handle being then turned, the tooth was 
extracted with the greatest ease. From that moment 
the horse began to feed, and rapidly improved in con- 
dition. In a short time he v/ent to work, and has done 
well." 

Surgeon 0. May, of Maiden, Eng., thus tells how he 
cured "A Case of Disease of the Jaw" (" Veterinarian," 
1834, p. 93): 

" I was requested by Mr. Earn, of Purleigh, to look 
at a horse which he told me had a ^cancer' in his jaw. 
I found my patient, a fine young chaise-horse, looking 
very poor, and having a constant discharge from the 
region of the root of the second low^er grinder. There 
v/as considerable enlargement of the bone, which led 
me to suspect disease of the tooth, and which, on ex- 
amination, proved to be true. On introducing a probe 
into the orifice, I found that it went through the tooth 
into the mouth. I was inform^ed that this supposed 
cancer had been under the treatment of a farrier, and 
that the poor beast bad been subjected to many pain- 
ful caustic applications. As I was satisfied that no 



THREE UPPER GRINDERS EXTRACTED. 179 

good could be done to tlie jaw as long as the tooth re- 
mained in it, I decided to extract it. I had an instru- 
ment made similar to the key used in human dentistry, 
with a handle like that of an auger. Having cast my 
})atient and lanced the gum, I fixed the instrument on 
the tooth and succeeded in extracting it, although it 
required nearly all my strength. Tliere was but 
trilling hemorrhage, and the 'cancer' soon got well. 
I think our patients are more frequently the subjects 
of toothache tlian we suppose. • Perhaps 'quidding' in 
many of them might be traced to a carious tooth." 

In a report of ten cases of diseased t^eth that were 
treated at the Edinburgh Veterinary College during 
tlie year 1845, the details of one is thus given in "The 
Veterinarian" (1845, p. 626): 

"A cart-horse was brought here with a profuse flow 
of white, clotty, and offensively smelling matter from 
the off nostril. The external plate of the superior 
maxillary bone on the same side was considerably 
elevated, and pain was evinced on pressing the part. 
There was no ulceration visible of the Schneiderian 
membrane, but the submaxillary lymphatic glands 
were somewhat enlarged. On examination there ap- 
peared to be disease of the superior maxilla, in which 
the grinder teeth were involved. Considering the 
extent to which the facial bones were affected, it was 
decided, as the only way of effecting a permanent cure, 
to extract the diseased teeth. The horse was cast, and 
by means of the ordinary tooth-key three of the upper 
back teeth were extracted. In a few days after the 
operation the discharge diminished in quantitv, and 
under the continued application of proper remedies it 
entirely subsided, and the horse is now well. 



180 TITE DEis"TISTRY OF THE TEETH. 

"There are in this, as in former reports, cases where 
the superior maxillary bone and its sinuses have been 
injured from the elongation of the grinders of the in- 
ferior maxilla, causing a nasal discharge iu many cases 
mistalien for that of glanders. They are easily reme- 
died by shortening the teeth with the cntting-forceps." 

Surgeon A. H. Santy says (" Veterinarian," 1875, 
p. 835): 

"On the 26th of June I bought a six-year-old mare. 
She continued to work till July 17th, when she was 
suddenly taken with a slight running from the near 
nostril, which greatly increased in twenty-four hours. 
The submaxillary gland on that side -swelled. There 
was slight tenderness of the throat and loss of appe- 
tite, which soon passed away. I showed the animal to 
a brother surgeon, and told him I thought of trephin- 
ing. He said: * Don't be in a hurry.' It struck me 
there might be something wrong with the grinders. I 
examined them, and found the fourth superior near 
side tooth with a depression on the outside and slightly 
raised from the surface of the other teeth. There was 
slight fetor from the food lodging there. I at once 
cast the mare, and with some difficulty extracted the 
tooth. I then dressed the wound and nursed the mare 
for a few days. The discharge from the nostril ceased 
in ten days. I have the mare now in constant work." 

The above case deserves consideration for several 
reasons. Thousands of horses with precisely the same 
symptoms have been killed because the surgeon could 
not discriminate between diseased teeth and glanders. 
The "slight tenderness of the throat and loss of appe- 
tite, which soon passed away," was the result of the pus 



*' DON'T BE IN A HURRY.'* 181 

finding an outlet, which gave partial relief. Surgeon 
Saoty acted on tlie advice, "Don't be in a hurry," and 
consequently had time to think. The depression on 
the outside of the tooth and its slight projection above 
• the common level, were signs that the trained eye only 
will detect. However, had the operation been delayed 
for a short time, in addition to the depression on the 
outside of the tooth, the gum would have been more 
or less shrunken, and the tooth, as a natural conse- 
quence, would have appeared longer.* Further, in- 
stead of the tooth being "slightly raised from the sur- 
face," it might have been beloAV it; for, the inflamma- 
tion having subsided, and the roots being shortened 
by the caries, it is liable to be forced deeper into the 
socket. Its next natural movement, the caries havin^- 
destroyed its periosteum, is to drop out altogether. 

As an offset to the foregoing cures, a few cases that 
terminated in death will be given. Surgeon Samuel 
Baker, in a letter to the editor of " The Veterinarian " 
(1845, p. 21G), says: 

"I was called in by a neighboring farmer to examine 
a two-year-old colt, which had to all apj^earance a polj'- 
pus as large as a cricket-ball growing out of the right 
nostril. Respiration through that nostril was stopped. 
In order to ascertain its nature, I had the colt cast, 
and found that the nostril was filled with a hard fleshy 
tumor, which distended the other nostril also. After 
making an incision through the ala and side of the 
nostril, I removed a portion of the tumor, over a pound 
in weight. But, as still no air passed through, and 

* Slirinkaf^e of tlie gum, accordinf^ to C. D. House, invariably 
follows caries of the roots of the teeth. 



182 THE DEHTISTRY OF THE TEETH. 

there seemed not the slightest chance of gaining a 
passage, I ordered the colt to be killed. 

" In dissecting the head I found that the cause pro- 
ceeded from a decayed tooth, at the root of which was 
a bag of matter about the size of a walnut, which by 
no possible means could relieve itself." 

Surgeon Baker does not say v/hich of the six teeth 
(of course it was an upper grinder of the right side) 
was diseased. The complications of the case appear to 
have been unusual, otherwise the bag of matter would 
have sooner or later found an outlet through the nos- 
tril. The extraction of the tooth would have probably 
afforded an outlet through the alveolus ; this failing, 
the effect of trephining the sinuses should have been 
tried. 

Surgeon William Smith, of JSTorwich, Eng., reports 
a case of caries of the roots of several grinder teeth, 
accompanied by a discharge from the nostril, which 
he admits he mistook for ozena. He says ("Veterina- 
rian," 1850, pp. 381-2): 

^^I was requested a few days ago to visit a horse 
which was supposed to be 'glandered.' I found the 
animal in a most emaciated and pitiable condition, 
with a copious greenish and very offensive discharge 
from the left nostril, with slight tumefaction of the 
gland on the same side. There Avas no appearance of 
ulceration, but the Schneiderian membrane had a 
leaden, dirty hue. Taking all the circumstances into 
consideration, I ordered the animal's destruction, but 
had its head sent to my infirmary. 

" Meeting Surgeon Gloag, of the Eleventh Hussars, 
I told him I thought I had a case of ozena. He ex- 



OifE TOOTH LOST AXD POUR DISEASED. 183 

pressed a wish to be present at the examination of the' 
head, and I was glad to avail myself of his assistance. 

"A longitudinal cut was made on each side of the 
septum nasi, and a transverse one at a line between 
the center of the orbits. Anotlier longitudinal cut, 
dividing the maxillary sinuses, was made just above 
the fangs of the grinder teeth on each side. By this 
means we had an opportunity of examining tlie sep- 
tum nasi on each side ; also tlie turbinated bones, and 
the frontal and maxillary sinuses. 

" On the left side we found an accumulation of pul- 
taceous food, covered v/ith thick pus, completely filling 
the maxillary sinus, and extending to the turbinated 
bones. The frontal sinus contained an accumulation 
of inspissated (thickened) pus, the septum nasi was of 
a leaden hue, as also the membrane covering the tur- 
binated bones, which was much inflamed and thick- 
ened, but there v/as no appearance of ulceration. 

*•' The difiieulty was to ascertain how the food got 
there. After careful search, it Vv'as very evident that 
it could not have passed through the nostril. We 
therefore gradually dislodged the Ibod and matter, 
searching for the former's entrance, and at last found 
a hole in the alveolar space belonging to the last 
grinder, the fang of which was completely gone, only 
a small portion of the crown itself remaining. The 
hole was sufficiently large to admit the little finger. 
The mystery was solved — the process of mastication 
had deposited the food in the sinus. The fourth 
grinder was absent, having been lost evidently from 
previous disease. 

" On examining the right side of the head we found 
the turbinated bones and membranes covering the 
septum nasi comparatively healthy, but we discovered 



184 THE DENTISTRY OF THE TEETH. 

a cyst, about the size of a walnut^ in the maxillary 
sinus. It contained limpid fluid, and occupied the 
space immediately over the fang of the fourth grinder 
tooth, which was decayed and quite loose, and beloiu"^ 
the level of the other teeth. The teeth of the lower 
jaw appeared healthy." 

Without further examination, Surgeon Smith sent 
the head to the editor of "The Veterinarian," who 

says : 

"The mare (that being the sex according to the 
teeth) we should take to have been about twenty years 
old. Her incisors are sound, and so are the grinders 
of the lower jaw. But in the near (left) upper jaw, 
the second, fourth, and sixth teeth are in a state of 
progressive decay, and the same is true of the fourth 
tooth of the off side. The vacuity caused by the de- 
fective last grinder has opened a passage to the an- 
trum, through which the food has passed, and thence 
into the near chamber of the nose, between the tur- 
binated bones, where it was discharged through the 
nostril. This accounts for the irritation on this side 
of the head, for the suppurated and even ulcerated 
condition of the Schneiderian membrane, and for the 
suspicious discharges. It was evident enough that 
there was no glanders. The very circumstance of ali- 
mentary matter being discharged through the nostril 
was enough to prove the contrary." 



Still another case of destroying a horse for what 
merely appeared to be glanders is recorded by Prof. 

* The italics are mine. Compare with comments on Surgeon 
Santy's cape, page 181. 



A GOVEENMENT HORSE'S HARD LOT. 185 

William Percivall iu his work entitled "Hippopath- 
ology" (vol. ii, p. 237). He says: 

"There are instances on record of carious teeth be- 
ing productive of such evil consequences as to lead, 
through error, to a fatal termination. The following 
relation ought to operate on our minds as a warning 
in pronouncing judgment in cases of glanders, or at 
least in sucli as assume the semblance of glanders : 

"A horse, the property of government, became a 
patient of Surgeon Cherry on account of a copious 
defluction of discolored and purulent matter from the 
near nostril, unaccompanied by submaxillary tumefac- 
tion, or by ulceration of the Schneiderian membrane. 
For two or three months the case was treated for 
glanders; but no improvement following, a consulta- 
tion was deemed necessary, the result of which was 
the horse was shot. 

" On examination of the head, the third upper left 
grinder proved to be carious, one-third of its fang be- 
ing already consumed and the remainder rotten. The 
formation of an abscess within its socket had loosened 
the tooth, and the matter flowing therefrom had estab- 
lished a passage into tlie contiguous cluimber of the 
nose. The antrum was also in part obstructed by the 
deposition of osseous matter. 

"This is a case which, but for the inquisitiveness of 
Surgeon Cherry, would have merged into that hetero- 
geneous class of diseases passing under the appellation 
of clironic glanders. 

"My father's museum contained several specimens 
of carious teeth. One was that of a grinder, the inte- 
rior of which was black and rugged, from being eroded 
by ulceration, and the fangs had from (he same cause 



186 THE DEI^TISTRY OF THE TEETH. 

mouldered away. Two others presented brittle exos- 
toses upon their sides, forming spacious cavities within 
and communicating with the contiguous teeth. One 
of them exhibited a perforation through which pus 
aj^peared to have issued. Both seemed to have been 
cases which had originated in internal injury." 

Prof. George Yarn ell closes his series of papers " On 
Some of the Diseases Affecting the Facial Eegion of 
the Horse's Head" ("Veterinarian," 18G7), by giving 
an account of a case of *osteo-sarcoma,' the disease, in 
his opinion, being caused by carious teeth. The case 
illustrates the importance of veterinary dentistry ad- 
mirably. He says : 

"Further to illustrate varieties of the diseases of 
the sinuses, I will relate a case of osteo-sarcoma which 
came under my care in July, 1862. I foand tlie horse 
had an offensive discharge from the left nostril. The 
face below the orbit was enlarged, and the eye slightly 
displaced in its cavity. I also found that the three 
last grinder teeth in the upper jaw of the affected side 
were quite loose in their sockets, from which a dis- 
charge of a highly fetid character issued. Percussion 
on the side of the face indicated extensive disease, and 
the enlargement readily yielded to pressure. As there 
was not the slightest prospect of a cure, I suggested 
that the animal be killed. 

'^Post-mortem Examination. — The outer walls of the 
sinuses, which were very thin, were first removed, dis- 
closing a mass of disease the seat of v/hich was oppo- 
site the fangs of the fourth grinder tooth, which was 
carious. This abnormal growth occupied the maxil- 
liiry, malar, lachrymal, and a portion of the frontal 
sinuses, and had also encroached upon the orbit to 



SWALLOWING A DISEASED TOOTH. 187 

such an extent as to displace the e3Tl)all. The outer 
surface' of the diseased mass was soft' in texture. It 
had a gelatinous appearance, and when pressed with 
the blade of the scalpel, a thin, watery fluid oozed from 
its surface. A section of it presented a grayish-red 
appearance, with lightish streaks of fibro-osseous mat- 
ter diverging from its roots and extending irregularly 
through its entire substance. The facial bones them- 
selves, in the region of the disease, had in some parts 
disappeared altogether, wiiile in others the cancelli 
were much enlarged, their osseous partitions pai-tially 
absorbed, and their interstices filled with a deposition 
of a fibro-cellular structure. 

" Such is a brief outline of this malignant and in- 
curable disease, wliich I have no doubt primarily arose 
from caries of the fangs of the grinder teeth." 

Prof. Renault, of Alfort, France, is the author of an 
interesting account of a very unusual case, namely, 
the swallowing of a diseased tooth by a horse, which 
appeared originally in the '' Recueil de Medicine Vete- 
rinaire'' for 183G. It is an argument against casting 
horses for the purpose of extracting their teeth, for 
had the horse been in a standing position the accident 
would not have occurred. When a horse's head rests 
upon the occiput, the muzzle pointing upward, it is as 
natural — the tooth being free of the forceps as well as 
the socket — for it to drop into the throat as it is for 
water to run down hill. The full history of the case 
is as follows : 

*' A post-horse, seven years old, had not fed well, and 
had been losinc: flesh durinof about three weeks. On 
the 2Gth of November, 1835, I suav him for the first 
time. The postilion told me that within the last two 



188 THE DEIS'TISTRY OF THE TEETH. 

days he had eaten with more difficulty and pain than 
before, and dropped ahnost the whole of the hay and 
corn from his mouth before it was perfectly masticated. 
He had also observed that during the mastication of 
his food tlie horse always inclined his head to the left 
side. 

"On examining the mouth, I easily recognized the 
cause of this difficulty of mastication. The gum, at 
the second grinder of the right lower jaw, was swollen 
and ulcerated, both within and without. The least 
pressure on the gum at this spot inflicted great pain, 
and the animal also suffered when the crown of the 
tooth was touched. On that portion of the jawbone 
contiguous to the diseased tooth, was a considerable 
swelling, hot and painful, which the postilion told me 
had existed for about twelve days. It was increasing in 
size every day. The breath w\as only slightly fetid, 
and there was nothing to indicate caries of the tooth. 
I expressed the opinion that the caries, if it existed, was 
confined chiefly to the root of the tooth, and that the 
ulceration of the alveolar septa beneath, of which there 
was no doubt, rendered its extraction necessary. 

" On the following day the horse was cast, and his 
mouth being kept open by the proper instrument, the 
key was applied to the tooth. It resisted my first 
effort to draw it, but, on the second trial, gave way 
with a peculiar sound, which made me suspect that it 
was broken. The instrument (gag) was then taken 
out of the mouth, in order that the tooth might 
escape, but, to my great surprise, no tooth could be 
seen, notwithstanding I carefully searched for it. It 
w^as now plain that the tooth had been swallowed. I 
then assured myself that the tooth had been entirely 
extracted, and as, during the operation, the frenulum 



OPENIN"G THE JUGULAK. 189 

of the tongue had been wounded, I deferred the cau- 
terization of the alveolus till the following day. 

*• As to the swallowing of the tooth, I gave mj^self 
very little concern. I did not think that so small a 
body was likely to form any serious obstruction in the 
intestinal canal, or that its temporary sojourn in the 
large intestine could become at all dangerous; so I 
merely directed tliat the mouth be frequently washed 
with warm water, and forbade the use of hard food. 

"29th. I again saw the horse, and no serious con- 
sequence had yet followed the operation. He ate bar- 
leymeal mash with appetite, and a small quantity of 
hay. Two hours afterward he was brought to the 
School. He was very uneasy, and his belly was enor- 
mously distended, the sweUing being principally on 
the right side, where the resonance was considerable 
on percussion. The horse was continually endeavor- 
ing to expel something from the anus, and the strain- 
ing w^as so great that I feared the rectum would pro- 
trude. The efforts were followed by small mucous 
dejections, mixed with portions of food. The mucous 
membrane was of a subdued red color. These symp- 
toms had been preceded by swelling at the flanks; 
colicky pains had followed, but they had ceased, 
and nothing now remained except the enlargement of 
the belly and the incessant effort to expel the faeces. 
The artery was full, but the pulse was almost imper- 
ceptible; the extremities were cold and the mucous 
membranes of a red violet color. The nostrils were 
convulsively dilated, respiration difficult and acceler- 
ated, and the walk staggering; the skin was covered 
with sweat, and, in a word, the animal presented every 
symptom of immediate suffocation. On this account I 
immediately opened the jugular and abstracted about 



190 THE DENTISTRY OF THE TEETH. 

twelve pounds of blood. The patient was very con- 
siderably relieved. I then ordered all four legs to be 
w^ell rubbed with essential oil of turpentine. 

''There now appeared to me a conuection between 
these symptoms and the swallowing of the tooth. But 
where was this tooth ? Entangled in the pyloric ori- 
fice of the stomach ? I could not perceive any symp- 
tom of gastric disease. Was it in the convolutions or 
the caical portions of the small intestines? How then 
could I explain the distention of the large intestines 
and the expulsive efforts, so violent and continued? 
It was more likely that the tooth was lodged either in 
the colon or the ca}cum, or in the irregularities of the 
floating colon, and partially or entirely prevented the 
passage of the faeces. It was hard to believe that in 
the lapse of two days the tooth could have reached the 
further part of the intestines. 

" Having determined on the nature of the disease, I 
was somewhat embarrassed to ascertain its precise seat. 
I attempted to introduce my hand into the rectum, 
but the circumvolutions of the bowels were so much 
distended with gas, and so completely filled the pelvis, 
and the mere introduction of my finger caused such 
violent efforts to expel the contents of the rectum, that 
I was forced to desist. 

'' In the meantime the swelling rapidly increased, 
and again threatened suffocation. I then determined 
to use the only means in my power to prevent this, 
namely, to puncture the caecum. This was effected 
with the trocar used for hoove in sheep, and in an in- 
stant the swelling subsided, and the symptoms of suf- 
focation disa])peared. I was then enabled to introduce 
my hand into the rectum, but I could not discover the 
situation of the tooth. While exploring the rectum, 



THE TOOTH IN" THE CmCJJ'il, 191 

liowever, the 'caniila' escaped from the csecum. The 
swelling now began again, and increased with extraor- 
dinary rapidity. I was about to plunge the trocar into 
the intestines once more, when I perceived that all 
treatment was useless. The animal was in the agonies 
of death, and in a few moments it expired. 

"The post-mortem examination took place immedi- 
ately after death. I found in the heart and lun^'s all 
the lesions which usually accompany death by suffoca- 
tion. The digestive canal was distended by gas. The 
stomach was half filled with barleymeal, but not a par- 
ticle of it was found througliout the whole extent of 
the small intestines, nor was there the slightest trace 
of inflammation of the mucous coat. The caecum con- 
tained a great quantity of blood-tinted fluid, but there 
was no lesion or redness on any part of its internal 
face to indicate the source of the blood. Probably it 
came from the wound made by the trocar. 

"In the cavity of the cJBCum, toward its point, we 
found the tooth ; but, I repeat it, there was no inflam- 
mation of its mucous membrane. There w^as, how- 
ever, a slight discoloration of the membrane toward 
the end of the colon ; it was of a slate color, and was 
probably caused by the sulphuretted hydrogen gas. 

"Are we to conclude that tlie death of the horse 
was caused by the tooth? However extraordinary 
such a conclusion may at first a])pear, I am very much 
inclined to believe that it affords the best explanation 
of the mystery. The horse had scarcely eaten for 
fifteen days. This long fast had produced a compara- 
tively empty condition of the digestive canal and an 
augmentation of its irritability up to the moment of 
the operation. The quietness of the hofse and his 
appetite and apparent health during the tv/o days pre- 



192 THE DEI^TISTRY OF THE TEETH. 

ceding his death, proved that the tooth passed without 
obstacle through the first part of the intestinal canal. 
Having arrived at the caecum, however, which was 
almost empty, and lying for a greater or less time at 
the inferior part of its mucous coat, its hard and irreg- 
ular surface produced irritation ; and as the contrac- 
tions of this intestine were not efiectual to seize the 
tootji and return it to the beginning of the colon, the 
prolongation of the irritation might suspend the diges- 
tive function of this viscus, augment its secretions, 
and cause the continual effort to expel the faeces. 
Hence also arose the gaseous distention of the abdo- 
men. As to the death of the horse, the tooth was only 
the indirect cause. The direct cause was suffocation, 
which was produced by the distention of the bowels." 

Prof. Bouley and Surgeon Ferguson report two 
fatal cases of swallowing teeth that came under their 
own observation. " In the first," they say, '^ the horse 
succumbed in a tympanitic affection, accompanied by 
extreme pain, and death was produced by asphyxia." 
The second case, judging by the short description of 
it in "The Veterinarian" for 1844, is the identical 
case just described by Prof. Bouley's fellow-townsman, 
Prof. Eenault. Messrs. Bouley and Ferguson further 
say: 

"Such, however, is happily not always the result of 
swallowing a tooth or the fragment of a tooth; but 
even the possibility of such a result ought to make 
the surgeon cautious. Moreover, the swallowing of a 
tooth may cause serious consequences at some future 
time. We refer to the formation of those productions 
called ^intestinal calculi.' The tooth, on account of 
its being indigestible, acts as the nucleus for the future 



SWALLOWIN"G A SOUi>rD TOOTH. 193 

calculus, as indeed may any similar body, which fact 
has been demonstrated by Prof. Morton, of the London 
Veterinary College, in an excellent paper on 'The For- 
mation of Calculus Concretions in the Horse.' ''* 

Surgeon W. A. Cartwright reports that he extracted 
three grinders from a 'quidding' mare, one of which 
she swallowed ("Veterinarian," vol. iii, second series, 
p. 277). The tooth was sound, which may account for 
the favorable result of the case. 

* Tlie Enterprise, publislied in Virginia, Nevada, in its issue 
for December 13, 1878, contains an article entitled " A Stone 
found in a Horse's Jaw," which is in substance as follows : " For 
a long time a lump has been noticed in the side of the jaw of a 
horse belonging to Superintendent Osbiston, of the Gould and 
Curry and Best and Belcher mines. It was near the jawbone, 
and no liniment had power to soften or drive it away. Yester- 
day a veterinary surgeon made an incision, and to his astonish- 
ment removed a stone about two inches long and one inch in 
diameter. It is yellowish-white in color, and apparently as hard 
as marble. Mr. M. M. Frederick, the jeweler, divided it longi- 
tudinally, and in its center was what appeared to be a petrified 
grain of barley, whicli was also divided longitudinally. Around 
this nucleus the stone had formed in regular layers, the rings of 
which could be distinctly traced. The material of which the 
stone was composed appeared to be the same as that of the in- 
crustations on the tubes of boilers. It is conjectured that*the 
grain of barley pierced the gum and imbedded itself in the flesh, 
and that the saliva, flowing in, deposited limy matter similar to 
that which is sometimes found on the teeth of horses as well as 
men. A small concretion having thus been formed, it gradually 
grew, the channel by which the grain of barley entered no doubt 
remaining open and allowing an inflow of saliva." 

The above case is another proof that Dr. Dunglison was right 
when he said that calculi "may form in every part of the animal 
body." 

9 



CHAPTER X. 

FKACTURED JAWS. 

How Caused, and how to Distinguish an Abrasion of the Gums 
from a Fracture of the Bone. — Replacing an Eye, Amputa- 
ting part of a Lower Jaw, taking a Fractured Tooth and 
Bones out through the Nostril, &c. 

Fractures of the jaws of the horse are of common 
occurrence. They may exist independently, but they 
are often complicated with and the cause of diseases of 
the teeth. Caries of the jawbone proper, and even 
some of the facial bones, is often communicated to the 
alveoli, and when necrosis ensues the destruction of 
the teeth is inevitable. This is as true in the case of 
the horse as in that of man. 

The rami (branches) of the lower jaw are common 
seats of fracture, a frequent cause of which is the use 
of sharp curved bits ; but rou^h usage by the rider or 
driver will now and then cause fractures even with a 
smooth bit. As a rule, at first, the gums only are 
affected; but in a short time the periosteum and bone 
are reached. Prof Varnell says : " If the matter that 
escapes be of a grayish-brown color and fetid, it wdll 
indicate disease of the bone ; but if it is from a sub- 
cutaneous abscess, the discharge will be simply of a 
puiTilent nature, and a speedy cure may be effected by 
the application of very simple remedies." 



SUEGEOX FLEMING'S DISCOVERY. 195 

When a fracture has been produced, inflammation 
and fetor will follow, and the horse loses his appetite. 
If the bone is removed and the horse is allowed to rest 
for a few daj^s, the wound will heal; otherwise the 
most serious consequences may follow- The removal 
of the bone may be effected sometimes soon after the 
fracture; but if, after cutting into the gum, it be found 
too firmly attached to the surrounding parts, it is bet- 
ter to wait a week or two that nature may loosen it. 
Bones an inch or more in length are often removed. 
Thus that which at first appears to be "only a sore 
mouth," may, if neglected, prove the ruin of a valuable 
horse. 

Fractures are often caused by external violence. A 
severe blow, accidental or otherwise, in the region of 
the roots of the teeth may cause a fracture that will 
necessitate the removal of both the bone and the teeth. 

"The lower jaw," says Prof. Youatt, "is more sub- 
ject to fracture than the upper, particularly at the 
point between the tushes and the incisor teeth, and at 
the symphysis (of the chin) between the two branches 
of the jaw. Its position, length, and the small quan- 
tity of muscle covering it, especially anteriorly, render 
it liable to fracture. The same circumstances, how- 
ever, combine to^render a reunion of the parts easy." 

The following extraordinary case of accidental frac- 
ture is reported by Surgeon George Fleming ("Veteri- 
narian," 1874, p. 694) : 

"' In 18G5, while stationed near Aldershot, I was 
driving one day in the neighborhood of Farnborough, 
when, in a narrow lane, our progress was somewhat 
checked by a farmer's wagon in front, which compelled 
us to travel at a walking pac2 for some distance. Dur- 



196 FKACTURED JAWS. 

ing this delay my attention was attracted to the sbaft 
horse, which had an enormous tumor on the I'ight side 
of its face. It had such a singular appearance that I 
dismounted from the carriage and induced the driver 
of the wagon to halt, when I inquired into the history 
of the case, and made an inspection of the tumor. It 
was as large as half a good-sized cocoanut, occupied 
nearly the whole side of the face^ and was literally 
a mass of what at first appeared to be fragments of 
bone, but which, on a closer examination, proved to 
be imperfectly developed gi-inder teeth. The tumor 
looked as if it were composed entirely of them. I was 
informed that, when two years old, the foal had taken 
fright and ran away, and in trying to get through a 
gate, a wooden stump ran into its face, making a large 
hole. The hole filled up, the tumor gradually formed 
on it, and since that time these 'bits of bone/ as the 
wagoner called them, were constantly shed from its 
surface. The growth was so large that the collar was 
passed over the head with great difficulty. I was so 
much interested in the case that I offered to keep the 
animal wdiile the removal of the tumor was attempted; 
but the farmer could not spare it from work at the 
time, and I did not have another opportunity.-' 

* 

The following accounts of cases of fractured jaws 

treated by various surgeons are from Prof. Youatt's 
work, " The Horse" (p. 44:5) : 

"^ Surgeon Cartwright had a mare in which the up- 
per jawbone was fractured by a kick at the point 
where it unites with the lachrymal and malar bones. 
He applied the trephine, and removed many small 
bones. The wound was then covered by adhesive 
plaster, and in a month the parts w^ere healed. 



MM. REVEL AND BOULEY'S SKILL. 197 

" Surgeon Claywortli reports the case of a mare that 
fell while being ridden almost at full speed, and frac- 
tured the upper jaw three inches above the corner in- 
cisors. The teeth and jaw were turned, like a hook, 
completely within the lower teeth. The mare was cast, 
a balling-iron put into her month, and the teeth and 
jaw pnlled back to their natural position; she was then 
tied so that she c.ould not rub her muzzle against any- 
thing, and was fed with bean-meal and linseed tea. 
Much inflammation ensued, but it gradually subsided, 
and at tlie expiration of the sixth week the mouth was 
healed, scarcely a vestige of the fracture remaining. 

" An account of a very extraordinary fracture of the 
superior maxillary bone is given in the records of the 
Royal and Central Society of Agriculture in France. 
A horse was kicked by another horse, fracturing the 
upper part of the superior maxillary and zygomatic 
bones, and almost forcing the eye out of its socket. 
Few men would have dared to undertake a case like 
this, but Monsieur Eevel shrank not from his duty. 
He removed several small bones, replaced the larger 
ones, returned the eye to its socket, confined the parts 
with sutures, slung the horse, and in six weeks he was 
well. 

" Surgeon Blaine relates that in treating a fracture 
of the lower jaw he succeeded by incasing the entire 
jaw in a strong leather frame. I have myself effected 
the same object by similar means. 

^' Prof. Bouley says (" Recueil de Medicine Yeteri- 
naire," 1*838) that he treated a horse whose lower jaw 
had been completely broken off at the neck — that is, 
at the point between the tushes and the corner incisor 
teeth, the detached bone being held by the membrane 
of the mouth. 



198 rilACTUKED JAWS. 

'•The liorse was cast, the corner tooth on the left 
side extracted, the wound thoroughly cleansed, and 
the fractured bones brought in contact. Holes were 
drilled between the tushes and the second incisors of 
both jaws, through which brass Avireswere passed. A 
compress of tow and a ligature, the bearing-place of 
the latter being over the tushes, surrounded the whole. 
Thus the jaws were a})parently fixed immovably to- 
gether. The wires yielded somewhat to the struggles 
of the horse, but the bandage of tow was tightened so 
as to retain the fractured edges in apposition. 

"Th.e wound now began to exhale an infectious odor, 
and gangrene was evidently approaching. M. Bouley 
determined to amputate the fractured portion of the 
jaw, its union to the main bone being apparently im- 
possible. The sphacelated portion of the jaw was en- 
tirely removed ; every fragment of bone that had an 
oblique direction was sawn away, and the rough por- 
tions which the saw could not reach wT,re rasped off. 

"Before night the horse had recovered his natural 
spirits, and was reaching for something to eat. On the 
following day he ate oats, and no one looking at him 
would have suspected that he had been deprived of his 
lower incisor teeth. The next day he ate hay. In a 
fortnight the wound was nearly healed." 

0. D. House, veterinary dentist, performed an unu- 
sual operation on a seven-year-old horse, the property 
of Mr. J. T. Allen, of Hartford, Conn. In 1876 a 
surgeon (?) made an incision in the right cheek and 
Icnoched out a large part of the fifth upper grinder. 
The violence of the operation fractured both the tooth 
and the jaw, imbedding a large fragment of the former 
in the bone above the socket. A year afterward, the 



SKILL VERSUS BRUTALITY. 



199 



horse still suffering and discharging matter from the 
nostril,, Mr. House was requested by Mr. Allen to ex- 
amine and if possible cure him. He failed, however, 
to discover the cause of the discharge, and it was not 
till the expiration of another year that he determined 
to probe the case to the bottom, the horse in the mean- 
time having suffered as usual. Making an instrument 
of the proper size and shape, he introduced it into the 
nostril, seized the tooth fragment and drew it forth, 
the horse at that instant making a deep expiration, 
which blew out several fragments of bone and a part 
of the root of the tooth. The animal made a good 
recovery.* 

* The Worcester, Mass., Spy for July 13, 1877, says : "C D. 
House, veterinary dentist, was in the city yesterday, operating 
on the horses of the Hambletonian Breeding Stud. A case was 
found where the grinders had been worn rough, and were be- 
sides slightly displaced, so that the horse in eating lacerated the 
lining of the cheek. Another case was where a colt's temporary 
tooth, after being partially forced from its place by the perma- 
nent, had remained fastened by one fang, and in such a position 
as to injure the gum while the animal was feeding ; and yet so 
nicely had the decaying tooth been lodged, that its presence was 
only detected by the oflfunsive odor. Several cases of inflamma- 
tion of the gums were found, which were accounted for by tlio 
presence of tartar. The tartar was removed. 

" Mr. House says that in all his experience he has not seen but 
two cases of glanders ; but he has known of hundreds of horses 
being killed for what was supposed to be glanders. The cause 
of the discharges from the nostrils in most of these cases arose 
from disease of the roots of the grinders. Horses are more sub- 
ject to dis -ases of the teeth, he says, than is generally supposed. 
The famous sire, Rysdyk's Hambletonian, died of the toothache, 
as have also many other blooded horses. 

" Mr. House's mode of operating is unique. He uses no gag, 
and the animal stands free. He passes his hands over the teeth 
of the most vicious horses, and was never yet bitten. He has 



200 FRACTURED JAWS. 

Surgeon J. P. Heatli thus describes a case of frac- 
tured jaw (" Veterinarian," 1878, p. 288) : 

" In May last I was called to see a horse that had 
been kicked by another horse. I found a transverse 
fracture of the left side of the lower jaw, between the 
first and second grinders, with lesion of the buccal 
membrane. The bone protruded inward, the tongue 
hung out of the mouth, and a constant flow of saliva 
existed. The animal's appetite was good, but there 
was of course a total inability to masticate. The horse 
was seventeen years old, but as the farmer (Mr. Gale, 
of Exniinster, Devon,) could ill afford his loss, I agreed 
to try to cure him. 

"I procured a wedge-shaped piece of wood, six or 
seven inches long by half an inch thick, which, after 
fitting it between the branches of the jaw^ I well be- 
smeared with warm pitch and pressed it tightly be- 
tween the fractured end of the bone. I then fixed 
another piece of wood of the same length, but two 
inches thick, which was also besmeared with pitch, 
outside the fracture, placing a bandage six inches wide 
over the whole, and tying it over the face below the 
eyes. 

operated on Edward Everett, Jud^e Fullerton, Emperor (owned 
by S. D. Houghton, of this city), and other notoriously vicious 
horses." 

The statement about Mr. House's mode of operating is strictly 
true. His control of a horse appears to be a gift. He never 
confines a horse, not even in performing the operation of castra- 
tion. In an " interview" with a reporter of The New York 8mi, 
printed in 1877, in reply to the question, " How do you know 
when a horse has tlie toothache ? " he said : " He telh me that he 
has it." So Mr. House must understand " horse-talk " as well as 
horse-dentistry. 



SURGEOJ^ HEATH'S SKILL. 201 

"For the first fortnight I do not tliink the animal 
took more than a gallon of the thin mashes and gruel 
with which he was supplied; but after that time the 
use of the muscles of the tongue began to return, and 
he was able to swallow a little. In about three weeks 
he could lick up oatmeal and oilcake gruel made thick, 
and in less than a month I removed the bandage (al- 
though the sphnts remained for six weeks), as by tliis 
time he could swallow a little pulped mangold grass, 
cut into chaff. For nine weeks he could only feed on 
cut fodder, when he was turned out to grass. At the 
present time he is in perfect health, feeding on ordi- 
nary diet and working constantly. The first and sec- 
ond grinders, which were loosened, appear now to be 
as firmly fixed as the others." 

The editor of "The Veterinarian" reports the case 
of a pony that came near starving from having a stick 
fastened in its mouth. No fracture of the bone was 
produced, but the account of the case is worthy of in- 
sertion here notwithstanding that fact, for it illustrates 
a class of mishaps to which the horse is subject. He 
says ("Veterinarian," 1855, p. 330): 

"A pony was turned into a pasture, and was not 
seen for several days. The owner found it standing in 
a corner of the field, looking dejected and thin, Avith a 
small quantity of viscid saliva escaping from its mouth. 
He took care of tlie pony for a few days, during w^hich 
time it took nothing but a little water, which it drank 
with great difficulty. Our attendance was now re- 
quested. Examination disclosed a stick about the size 
of one's finger, firmly wedged across the palate, be- 
tween the corner incisors. Its pressure had produced 



202 TREATMENT FOR ABRASED GUMS. 

extensive sloughing, so thafc the bone was completely 
exposed. The pain was so great that the poor animal 
stoutly resisted our efforts to remove the cause of its 
suffering. This, however, was soon done, and the parts 
being cleaned with tepid water, were afterward dressed 
with Tinct. Myrrhae. Little after treatment was nec- 
essary beyond the daily application of the tincture, a 
mash diet, and the substitution of oatmeal gruel for 
plain water." 



CHAPTER XI. 

THE TEETH AS IIs"DICATORS OF AGE. 

Their various ways of Indicating Age.— The "Mark's" Twofold 
Use. — The Dentinal Star. — Marks with too much Cement. — 
Tricks of the Trade. — Crib-biting. — Signs of Age Independ- 
ent of the Teeth. 

The incisor teeth of the horse, which, as before said, 
differ "from those of all other animals by the fold of 
enamel which penetrates the body of the crown, from 
its broad, flat summit, like the inverted finger of a 
glove," indicate age (1) by their cutting; (2) by their 
growth; (3) by their shedding; (4) by their marks;* 
(5) by their change of shape ; (6) by their change of 
color; (7) by their length, and (8) by the degree of 
their outward inclination. The cutting, growth, and 
shedding (of the tushes and grinders as well as the in- 
cisors — the cutting and shedding occurring at com- 
paratively regular periods, and the growth being grad- 
ual), indicate age from birth till about the sixth year; 
tlie marks of the lower incisors from the sixth month 
till the eighth year; those of the upper incisors, though 

* Prof C. S. Tomes says "the mark exists in Hipparion, but 
not in the earlier progenitors of the horse." Prof. O. C. Marsh 
says : " The largo canines of Orohipous became gradually re- 
duced in the later genera, and the characteristic mark of the 
incisors is found only in the later forms." 



204 TSE TEETH AS i:srDICAT0K3 OF AGE. 

perhaps less reliable, during the same period, and for 
about four or five years longer (say the twelfth or thir- 
teenth), and the change in shape,* color, and position 
from about the seventh year till old age. The change 
in the shape of the teeth is caused by their wear and 
growth, the wear counteracting the growth and the 
growth the wear. 

hi foals and young horses the marks are prol^ably 
the surest guides by which to judge of the age. One 
peculiarity of them is that, as the teeth wear down, 
they approach the jjosterior edge. Besides their utility 
in indicating age — being composed of enamel (the ad- 
amantine substance) — they greatly enhance the dura- 
bility of the teeth — that is, during the first third of 
the horse's life. As a rule the variations in the size 
and appearance of the marks will be as follows: f 

At six months of age they are oblong and distinct 
in the central incisors, and if not already visible in the 
dividers, will become so before the seventh month. 

At one year they are shorter and less distinct in the 
centrals, and are becoming so in the dividers, but are 
large and plain in the corner teeth. 

At one year and a half they are small and round in 
the centrals, are diminished in size in the dividers, but 
are still large and distinct in the corners. 

At two years they are no longer visible in the cen- 
trals (in some cases these teeth are even shed at this 
period) ; they are smaller and rounder in the dividers 
and still plain in the corners. 

* Surgeon W. A. Cherry, of England, says the shape and gen- 
eral character of the teeth are much better criterions of age at 
all periods of life than the marks/ 

f For the dimensions of the marks (Surgeon Hughes's mea- 
surements), S3e page 58. 



WHAT MAY PUZZLE A KOVICE. 205 

At two years and a half the centrals are shed; the 
marks are faint in the dividers, but are distinct in the 
corners. 

At three years the permanent centrals are nearly 
grown ; the marks in the dividers are just visible, and 
have become smaller in the corners. 

At three years and a half the marks in the centrals 
are long and very distinct; the dividers are shed, and 
the marks in the corners are foint. 

At four years the marks in the centrals show the 
effects of wear, but are still long and distinct ; the per- 
manent dividers are growing, and the marks in the 
corner teeth have almost disappeared. 

At four years and a half the marks in the centrals 
are still large and distinct, and the dividers are about 
grown. The contrast between the large permanent 
incisors and the small temporary corner teeth, which 
have lost their marks, is striking at this age. 

At five years the marks in the centrals are getting 
smaller and rounder, but are large and distinct in the 
dividers ; the corners are usually shed at this age. 

"At six years," says Prof. Youatt, "the marks of 
the central nippers are worn out. There will, however, 
still be a difference of color in the center of the tooth. 
The cement filling the hole made by the dipping of 
the enamel will present a brow^ner hue than the other 
part of the tooth. It vn]\ be distinctly surrounded by 
an edge of enamel, and there will remain even a little 
depression in the center, and also around the case of 
enamel ; but the deep holes in the center of the teeth, 
with the blackened surface wdiich they present, and 
also the elevated edge of enamel, will have disappeared. 
Persons little accustomed to horses are often puzzled 
here. They expect to find a plain surface of uniform 



206 



THE TEETH AS INDICATORS OF AGE. 



color, and know not what conclusion to draw when 
they see both discoloration and irregularit^y." The 
marks in the dividers are much reduced in size, but 
those of the corner teeth are large and distinct. 

At seven years the marks disappear from the divider 
incisors, and at eight from the corner teeth. 

Monsieur Girard thus describes the changes in shape 
of the incisors, referring also to the disappearance of 
the marks in the upper teeth: 

^* At nine the central incisors become rounded, the 
dividers oval, and the corner teeth narrower. The cen- 
tral enamel (mark) diminishes and 
approaches the posterior edge. 

"At ten the dividers are rounder, 
and the central enamel is very near 
the posterior edge and rounded; at 
eleven they have become rounded, and 
the enamel has disappeared. 

"At twelve the corner teeth are 
rounded. The yellow band is larger, 
and occupies the center of the wear- 
ing surface. 

"At thirteen all the lower incisors 
are rounder; the sides of the centrals 
are becoming longer. The central 
enamel remains in the upper corner 
teeth, but is round and approaching 
the posterior edge. 

"At fourteen the lower central in- 
cisors have a triangular appearance; 
the dividers are becoming long at their sides. 

"At fifteen the central incisors are triangular, and* 
the dividers are becomino- so. 




The forms successive- 
ly assumed by the dental 
table of an incisor in con- 
sequence of fiiction.— 4. 
Chauceau. 



CAUSE OP THE YELLOW COLOR. 207 

*'At sixteen the dividers are triangular, and the cor- 
ner teeth are becoming so. 

*' At seventeen the corner teeth, like the dividers and 
centrals, have become triangular, the sides of the tri- 
angles being equal. 

"At eighteen the lateral portions of the triangles 
lengthen in succession— first in the centrals, next in 
the dividers, and then in the corners; so that at nine- 
teen the lower centrals are flattened from one side to 
the other; at twenty the dividers are flattened, and at 
twenty-one the corners also are." 

The three following extracts give some idea of the 
difficulties to be encountered in judging the age by 
the teeth. Prof. Youatt says : 

"Stabled horses have the marks sooner worn out 
than those at grass, and a 'crib-biter' may deceive the 
best judge by one or two years. At eleven or twelve 
the lower nippers change their original upright posi- 
tion and project forward. They become of a yellow 
color, the cause of which is that the teeth grow to 
offset their wear ; but the enamel which covered their 
surface when they were j^oung cannot be repaired, and 
that which wears this yellow color in old age is the 
part which was formerly in the sockets. The gums 
recede and waste away, and the tushes wear to stumps 
and project outward." 

Surgeon Ewd. Mayhew says ("The Horse's Mouth: 
Showing the Age by the Teeth") : 

" That the teeth of the horse denote age appears to 
have been a very ancient belief, which the experience 
of centuries has not changed. Within certain limits 



208 THE TEETH AS INDICATORS OF AGE. 

the belief is well founded, for perhaps no development 
is more regular than the teeth of the horse, and no 
natural process so little exposed to the distortions of 
artifice. We are, nevertheless, not to expect that the 
animal carries in its mouth a certificate of birth, writ- 
ten in characters so deep that they cannot be obliter- 
ated or misinterpreted. He who would judge of the 
age by the teeth must study them, and be prepared to 
eucounter difficulties. In proportion as he has done 
the one, and is enabled thereby to overcome the other, 
will be his success. The qualified judge alone will 
read the teeth correctly. He will make allowance 
where certain marks are indistinct or absent, and he 
will be cautious in pronouncing an opinion. The vet- 
erinary practitioner knows that the teeth are worthy 
of attention, and he feels that their indications, scien- 
tifically interpreted, will seldom mislead." 

Surgeon J. H. Walsh, in his excellent work, "The 
Horse; in the Stable and in the Field," says: 

"In order to be able to estimate the age of the horse 
by his teeth, it is necessary to ascertain, as nearly as 
may be, the exact time at which he puts up his milk 
teeth, and also the periods at which they were replaced 
by the permanent. Finally it becomes the province 
of the veterinarian to lay down rules for ascertaining 
the age from the degree of attrition which the perma- 
nent teeth have undergone. For these several purposes 
the horse's mouth must be studied from the earliest 
period of his life up to old age." 

Judging the age by the teeth is even more comj)li- 
cated and difficult than is shown by the foregoing ex- 
tracts. Among other complications worthy of consid- 
eration are the following: 



LIKE CREEDMOOR MARKS, HARD TO HIT. 209 

About the ninth year a mark, which is sometimes 
mistaken for the infundibnlum, or mark proper, ap- 
pears on the central incisors. M. Girard named it the 
dentinal'^ stctr^ but it is also called the fang-hole and 
secondary mark. Dentinal star is perhaps the most 
proper name, for the mark is "due to the presence of 
secondary dentine, into which the remains of the pulp 
has been converted." It may be distinguished from 
the first formation of dentine by its yellow tint. The 
dentinal star may not afford, as some authors claim it 
does, reliable data by which to judge of the age, but 
its presence is 'prima facie, evidence that the tooth has 
been worn to the original pulpal cavity. f The more 
the teeth wear, it is said, the plainer the star becomes. 

The marks of some teeth arc disproportionately 
composed of cement, a fact Prof A. Chauveau says he 
is not aware has ever been taken into account in "cal- 

* The reason for using the word dentinal in preference to den- 
tal, in the above as well as in many other cases throughout this 
work, is very clearly and forcibly given in a reference note (by 
Prof. Owen) on page viii, 

f Dr. John Hunter says (" The Human Teeth," pp. 50-1) : " A 
tooth very often wears down so low that its cavity would be ex- 
posed if no counteracting alteration were produced in it. To 
prevent this Nature has taken care that the bottom of the cavity 
shall be filled by new matter in proportion as the crown of the 
tooth is worn. This new matter is easily distinguished from the 
old, for when a tooth has been worn almost to the neck, a spot 
may be seen in the center, which is more transparent and at the 
same time of a darker color (occasioned in some measure by the 
dark cavity under it), and generally softer than the surrounding 
parts. Any one may be convinced of the truth of the matter by 
taking two teeth of the same kind, one just full-grown, the other 
worn almost to its neck. In the latter the dark spot is visible, 
and if as much material is cut from the former as has been worn 
from the latter, its cavity will be cut through." 



210 THE TEETH AS Il^DICATORS OP AGE. 

culating the progress of wear." Such teeth would soon 
wear out, for there is as much difference in the density 
of cement and enamel as between cartilage and bone. 

The obliteration of the mark may be hastened in a 
small or medium-sized tooth by the friction of one that 
is abnormally large, while a stunted or dead tooth n^ay 
never lose its mark. 

The more upright the teeth the faster they wear. It 
is said that the crowns will be worn to the extent of a 
quarter of an inch between the fifth and sixth years 
(when they are most upright), while only about that 
quantity of material will wear away between the twen-, 
tieth and twenty-fifth years. 

A horse's food is a matter also to be taken into ac- 
count. The mastication of grass, carrots, turnips, 
potatoes, bread, &c., does not cause much wear to the 
teeth. However, when grass is procured by grazing, 
the incisors suffer much friction — caused, not by the 
grass, but by the teeth grinding one another, for they 
meet edge to edge, and are employed in this occupa- 
tion for hours, whereas a ''feed" of com is shelled in 
a few minutes. In the former case the incisors suffer 
great friction ; in the latter, the grinders. Again, it is 
said that "horses fed on salt marshes, where the sea- 
sand is washed among the grass, or on sandy plains or 
meadows, are affected by the increased friction of their 
teeth." But no matter how soft a horse's food may 
be, if he is addicted to the vice called "crib-biting," 
his teeth may be ruined before those of the corn-fed 
horse have even lost their marks. 

Several trade tricks are also to be noted. Of "bish- 
oping," Prof Youatt says : 

" Dishonest dealers resort to a method of imitatins: 



youatt's compliments to bishop. 211 

the mark in the lower nippers. It is called Bisliopingy 
from the name of the scoundrel who invented it. The 
horse of eight or nine years is thrown, and with an 
engTcivc/s tool a hole is dug in the now almost plain 
surface of the corner teeth, its shape resembling the 
mark in those of a seven-year-old horse. The hole is 
then burned with a heated iron, and a j)ermanent 
black stain is left. The next pair of nippers are some- 
times lightly touciied also. 

''An unprofessional man would be easily deceived by 
this fraud, but it cannot deceive the trained eye of the 
horseman. The irregular appearance of the cavity, 
the diffusion of the black stain around the tushes — 
the sharp points and concave inner surface of which 
can never be given again — the marks on the upper nip- 
pers, together with the general conformation of the 
horse, will prevent deception. Moreover, in compar- 
ing the lower with the upper nippers, unless the oper- 
ator has performed on the latter also, they will be 
found to be considerably more worn than the lower, 
the reverse of which ought to be the case. Occasion- 
ally a clever operator will burn all the teeth to a prop- 
erly regulated depth, and then a practiced eye alone 
will detect the imposition." * 

* Rough oisr the Russians. — Surgeon John C. Knowlson 
makes the following open confession (" The Complete Farrier, 
or Horse Doctor," p. 150): "I was hired by Anthony Johnson, 
of Wincolmlee, Hull, as farrier to a number of horses that were 
goinj^ to ^loscow, Russia. We had a little gTay, seventeen-year- 
old liorse, named Peatum, whose mouth I bishoped. He passed 
for six years old, was the first horse sold, and brought £oOO, 
Enp^lish money ! I only mention this as a caution to horsemen."' 

Surgeon Knowlson could liave evidently beaten the late Pres- 
ident Lincoln in a (wooden) horse trade. 



212 THE TEETH AS IITDICATORS OF AGE. 

Of a deception practiced by sellers of two-year-old 
foals, namely, passing off an early two-year-old for a 
late three-year-old, Prof. Youatt says: 

" The age of all horses used to be reckoned from 
May, but some are foaled as early as January. A two- 
year-old foal of the latter date may, if it has been well 
nursed and fed and has had its central nippers drawn 
(that three or four months' time may be gained in the 
appearance of the permanent), be sold at the former 
date for a three-year-old. To horsemen, howev^er, the 
general form of the animal, the little development of 
the forehand, the continuance of the mark in the divi- 
der nippers, its more evident existence in the corner 
ones, and some enlargement or irregularity about the 
gums, from the violence used in forcing out the teeth, 
are a sufficient security against deception." 

And again of four-year-old foals: 



"Now, more than at any other time, will the dealer 
be anxious to put an additional year npon the animal, 
for the difference in strength, utility, and value be- 
tween a four-year-old colt and a five-year-old horse is 
very great. But the lack of wear in the central and 
divider nippers, the small size of the corner ones, the 
little growth of the tushes, the low forehand, the leg- 
giness of the colt, and the thickness and little depth of 
the mouth, will at once detect the cheat." 

The following is Prof. Youatt's description of crib- 
biting and its effect on the teeth ("The Horse/' pp. 
511,519): 

^^ The horse lays hold of the manger with his teeth, 
violently extends his neck, and then, after some con- 



COLICKY ClUB-BITERS. 213 

vulsive action of the throat, a slight grunting is heard, 
accompanied b}^ a sucking in of air. It is not an effort 
at simple eructation, arising from indigestion, but is 
merely the inhalation of air. It takes j^lace with all 
kiuds of diet, and when the stomach is empty as well 
as when it is full. 

" The effects of crib-biting are plain enough. The 
teeth are worn away and occasionally broken, and in 
old horses to a very serious degree. Sometimes graz- 
ing is rendered difficult or almost impossible. Coru is 
often wasted, for the horse will frequently 'crib' with 
his mouth full of it, and the gi-eater part of it will fall 
over the edge of the manger. Much saliva escapes also, 
wdiich impairs digestion. Crib-biting horses are more 
suliject to colic than others, and to a species difficult 
of treatment and frequently dangerous. 

''The only remedy is a muzzle, with bars across the 
bottom sufficiently wide to allow the horse to pick np 
his corn and pull his hay, but not to grasp the edge of 
the manger. Some recommend turning out for five or 
six months; but this will never succeed except with 
young horses, and rarely with them. Tlie old crib- 
biter will substitute the gate for the manger. We have 
often seen him galloping across the field for the mere 
object of having a gripe at a rail." 

Prof. Youatt further says that the vice is a species 
of unsoundness, having been so decided in the courts. 
It is often the result, he says, of imitation, but oftener 
the consequence of indigestion. Mischief, he says, is 
another cause of it. 

The mouth, it is said, is broader at seven years of 
age than at any other time; but, so far as judging the 
age is concerned, this fact (assertion) is of little prac- 



214 THE TEETH AS INDICATORS OF AGE. 

tical use. The facts that follow, however, are of more 
or less use, and are worthy of perusal. Prof. Youatt 

says : 

'^ The indications of age, independent of the teeth, 
are deepening of the hollows over the eyes ; wrinkles 
over the eyes and about the mouth ; gray hairs, par- 
ticularly over the eyes and about the muzzle; the 
countenance and general appearance; thinness and 
hanging down of the lips; sharpness of the withers; 
sinking of the back; lengthening of the quarters, and 
the disappearance of windgalls, spavins, and tumors of 
every kind. * ^ * ^1^ mne or ten the 'bars' of 
the mouth become less prominent, and their regular 
diminution will designate increasing age." 

Of another deception Prof Youatt says: 

" We form some idea of the age of the horse by the 
depth of the pits above the eyes. There is at the back 
of the eye a quantity of fatty substance, on which it 
may revolve without friction. In aged horses, and in 
diseases attended with general loss of condition, much 
of this disappears. The eye becomes sunken, and the 
pit above it deepens. Dishonest dealers puncture the 
skin, and, with a tobacco-pipe or tube, blow into the 
orifice till the depression is almost filled. This, with 
the aid of 'bishoped' teeth, may deceive the unwary. 
The fraud may be easily detected, however, by press- 
ing on the part.'' 

"Frank Forester" (William Henry Herbert), says 
(" The Horse of America," vol. i, p. 72) : 

" Much stress is laid by many persons on the depth 
of the supra-orbital cavities, and more yet on the length 
and extreme protrusion of the nippers beyond the 



SUNKEN PITS AI!TD HOLLOW BACKS. 215 

gums, as also, in a less degree, on the hollowuess of the 
back. All these are doubtless indications of age; but 
I have many times seen colts — got by stallions in ex- 
treme oge — having all these indications of advanced life 
in a degree scarcely inferior to those of their sires, be- 
fore they had yet acquired a full m-outh, much less lost 
the mark. And more than once I have seen foals, 
newly dropped, with the deep supra-orbital cavities 
and hollow backs bequeathed to them by their aged 
sires before they had got their colt's teeth.'' 



CHAPTER XII. 

THE TRIGEMIKUS OE FIFTH PAIR OF KERVES. 

Its Nature and tlie Relation it bears to the Teeth. — Its Course in 
tlie Horse and in Man. 

The thread-like nerves of the teeth are derived from 
the superior and inferior maxillary branches of the 
trigeminus or fifth jiair of nerves. In the horse these 
branches are four or five times as thick as a ribbon 
and about five-eighths of an inch wide. The ophthal- 
mic branch is smaller and shorter, its course extend- 
ing only from the brain to the eye, while that of the 
two former extends to the lips, running parallel to and 
about an inch from the roots of the grinder teeth.* 

The description of the trigeminus and its course is 
from a lecture by Prof. Youatt to veterinary students, 
and may be found in "The Veterinarian" for 1834 
(p. 121). In the first part of the lecture the nature of 
the trigeminus— its double origin and function — is 
expatiated upon, a summary of which is that the sensi- 
tive and motor roots, are contained Vv^ithin the same 
sheath; that the sensitive root is so much larger and 
its fibrils so much more numerous than the motor that 

* For the preparation of an anatomical specimen showinir the 
g-eneral course of the trie^eminns, I am indebted to Prof. J. M. 
Heard, of the New York College of Veterinary Surgeons. 



THE Two ROOTS. 217 

it may still be called the sensitive nerve of the face; 
that the trigeminus is the only nerve of the brain that 
bestows sensibility to the face, except a few branches 
from the cervicals, w^hich may be traced to the lower 
part of it ; that there arc some anatomical facts which 
incontestably prove that the motor nerve exists : that 
Sir Charles Bell laid the root of the trigeminus bare in 
an ass immediately after the animal's death, and that 
on irritating the nerve the muscles of the jaw acted 
and the jaw closed; that he divided the root of the [ 
nerve in a living animal, and the jaw fell;* that he 

* " Re-establish:\ient of Sensibility after Resection 
OF Nerves. — A memoir by MM. Arloing and Tripier was read 
before the French Academy, November 28tb, on the efiFect of re- 
section of certain nervous trunks. Clinical facts have several 
times shown tbat after wounds which have altered or destroyed 
a portion of a nerve, sensibility returns in the integuments to 
which the nerve is distributed. MM, Arloing and Tripier made 
nervous resections in dogs, and saw sensibility reappear after a 
certain time in the integuments to which the branches of the 
nerve were distributed, and in the peripheral end of the nerve 
itself." — Popular Scisnce Eevieio, 1867. 

"How Motor-Nerves End in NoN-STrviATED Muscitlar 
Tissue. — A very valuable communication stating the results of 
M. Henocque's researches has been published in "I'Archives de 
Physiologie," and may be thus abstracted : 1. The distribution 
of the nerves in smooth muscle is not only identical in man and 
other vertebrate animals in which it has been observed, but is 
essentially similar to all the organs containing smooth muscle. 

2. B^^foro terminating in the smooth muscle, the nerves form 
three distinct plexuses or networks — (a) a chief or fundamental 
plexus, containing numerous ganglia, and situated outside the 
smooth muscle ; (b) an intermediate plexus ; and (c) an intra- 
muscular plexus, situated mtliin the fasciculi of smooth fibers. 

3. The terminal fibrils are everywhere identical. They divide 
and subdivide dichotomously, or anastomose, and terminate by 
a sliglit swelling or knob, or in a punctiform manner. The ter- 

10 



218 THE FI]?TH PAIR OF KERYES. 

divided the superior maxillary branch on both sides, 
the animal losing the power of using the lips; that 
Mr. Mayo divided the root of both the superior and 
inferior maxillary, the result being that the lips no 
longer remained in perfect apposition, and the animal 
ceased to use them in taking up his food; that the 
sensitive root, or a portion of it, after entering the cav- 
ernous sinus, swells out into or passes through a gan- 
glion, and that the motor root can be traced beyond 
the ganglion, uniting afterward with its fellow and 
forming the perfect nerve; that the ganglion, being 
composed of sensitive fibrils only, resembles a brain. 

minal swellinof appears to occupy different parts of the smootTi 
muscular fiber, but most frequently to be in the neighborhood 
of the nucleus, or at the surface of the fibers, or, lastly, between 
them." — The Monthly Microscopical Journal, 1870. 

" Structure op Nerves. — M. Roudanoosky says that the 
primitive elements of nerves are tubes having- a pentagonal or 
hexagonal configuration. As to their' constitution, he says that 
every nerve has a substratum of brain-matter, and also of the 
spinal marrow, and probably of the ganglionic matter also. The 
gray matter, he says, is the fundamental nervous substance, and 
plays the principal part in the functions." — " Veterinarian^' 
1S65, p. 313. 

In a letter to his brother, G. J. Bell, written in 1807, Sir 
Charles says : " I consider the organs of the outward senses as 
forming a distinct class of nerves. I trace them to corres]X)nd- 
ing parts of the brain, totally distinct from the origin of the 
others. I take five tubercles within the brain as the internal 
senses. I trace the nerves of the nose, eye, ear, and tongue 
j to these. Here I see established connection ; there, the great 
mass of the brain receives processes from the central tubercles. 
Again, the great masses of the cerebrum send down processes 
or crura, which give off all the common nerves of voluntary mo- 
tion. I establish thus a kind of circulation, as it were." — Medi- 
cal Gazette. 



THE COURSE OF THE NERVE. 219 

Prof. Youatt's description of the course of the tri- 
geminus is as follows : 

"The trigeminus has been described as springiug 
by a multitude of fllaments from the crura cerebelli, 
and forthwith running for safety into the cavernous 
sinuses, and there suddenly enlarging into or passing 
through a ganglion. The nerve, as its name implies, 
divides into three parts, the division taking place in 
the cavernous sinus, after the superior or sensitive 
root has been joined by the inferior or motor root. 
Each part, before it leaves the cranium, assumes a dis- 
tinct investment of dura mater. The branches are 
named, from the parts to which they are destined, the 
Ophthalmic, the Superior Maxillary, and the Inferior 
Maxillary. 

"The opMhalmic is the smallest of the three. It is 
formed within the sinus, where it is in conjunction 
wdth the superior maxillary, v/hich it soon leaves, and, 
passing through the foramen lacerum into the orbit, 
subdivides and forms three distinct branches — the 
Supra-orbital (the frontal), the Lachrymal, and the 
Lateral Nasal (the nasal). The supra-orbital climbs 
behind the muscles of the eye, giving filaments to the 
rectus superior and the superior oblique, and some 
also to the fatty matter of the eye. The main branch, 
escaping through the superciliary foramen, is soon lost 
in ramifications on the elevator of the superior eyelid, 
the integument of the forehead, and the periosteum. 
The lachrymal, as its name implies, is chiefly concerned 
with the lachrymal gland; a few ramifications, how- 
ever, are sent to the conjunctiva and also to the ciliary 
glands of the upper eyelid, while a distinct twig of it 
passes out at the angle between the zygoma and the 



220 THE FIFTH PAIR OF KERVES. 

frontal orbital process, where it anastomoses with the 
sapra-orbital and with ramifications from the superior 
maxillary. It is also lost on the integument and 
muscles of the forehead. The lateral nasal is the 
largest of the three. Almost at its beginning we ob- 
serve the filaments that help to form the Ophthalmic 
Ganglion. They are more numerous and more easily 
traced in some of our domesticated animals than in 
others, and the ganglion itself is differently developed, 
but for what physiological purpose I know not. It is 
comparatively larger in the ox than in the horse, and 
sends more filaments to the iris. Four distinct fila- 
ments may be traced in the ox, but seldom more 
than two in the horse or the dog. To these fila- 
ments others of the ophthalmic, that have not passed 
through the ganglion, afterward join themselves; so 
that the ciliary are also minute compound nerves of 
motion and sensation.* 

* " The best account, however, of this is <?iven by Dr. Jonas 
Quain (' Qaain's Anatomy,' p. 7fi8). He considers the ganglion 
as a center of nervous influence — a little brain, as it were — and 
the filaments which some anatomists describe as composing, he 
speaks of as branches given out from it. ' It lies,' says he, 
' within the orbit, about midway between the optic foramen and 
the globe of the eye, and is inclosed between the external rectus 
muscle and the optic nerve. It is exceedingly small and, owing 
to its being imbedded in the soft adipose tissue which fills tlie 
interstices of the different parts within the orbit, difficult to find. 
Its branches are the following: From its anterior border from 
sixteen to twenty filaments issue, which proceed forward to the 
surface of the sclerotic, and pierce it through minute foramina. 
These are the ciliary nerves. In their course to the globe of the 
eye they are joined by one or two filaments derived from the 
nasal nerve, but they do not form a plexus (an interlacement). 
They become, however, dispersed or divided into two fasciculi, 
one above and the other below the optic nerve, the latter being 



THE OPHTHALMIC NERVE. 221 

"The ophthalmic nerve, after running between the 
rectus superior and the retractor muscles, gives a 

the more numerous. They pass between the choroid membrane 
and the contiguous sui'face of the sclerotic — lodged in grooves in 
the latter — and on reaching the ciliary li^^ament, pierce it, a few 
appearing to be lost in its substance, while all the rest pass in- 
ward and ramify in the iris. From the posterior border of the 
ganglion, which seems as if terminated by two angles, two 
branches issue, one of which passes backward and upward to 
the nasal branch of the ophthahnic nerve, appearing to be the 
medium of communication between the ganglion and the rest of 
the ganglial system, by being prolonged to the carotid plexus. 
The other, the shorter branch, passes downward and backward 
to the inferior oblique branch of the motor nerve of the eye.' 

"For my own part," says Prof. Youatt, "I am now disposed 
to be very much of Dr. Quain's opinion. It was not fitting that 
the motions of the iris should be under the control of the will — 
they should respond to the varying intensity of the light." — W. 
Youatt in " Veterinarian" for 1S36, p. Jfi. 

Mou3. Cuvier says : " It divides into two ramifications, one of 
which proceeds toward the optic, unites with the small branch 
of the third pair, and by this union produces a nervous enlarge- 
ment called the lenticular or ophthalmic ganglion. Tiiis gan- 
glion usually sends off the ciliary nerves, disposed in two bun- 
dles. They are each composed of several filaments, which enter 
the globe of the eye obliquely. The iris receives a great num- 
ber of small ramifications from the ciliary nerves, which, after 
having perforated the sclerotic and passed around the choroides 
longitudinally, like ribbons, but without penetrating it, are lost." 
— " Comparative Anatomy" Vol. II, j)- '^06. 

Prof. W. Percivall says: " Upon the outer side of the optic 
nerve, between i t and that part of the motor oculi from which 
the branch nerves spring, is situated the ophthalmic ganglion. 
This little body is principally constituted of branches from the 
third pair, but it receives a filament or two from the sixth. The 
nervous threads transmitted by the ganglion surround the sheath 
of the optic nerve, and pursuing their course over it, penetrate 
the globe of the eye, and run to be dispersed upon the iris."— 
"Anatomy of the Horse " p. 336. 



222 THE FIFTH PAIR OF KERVES. 

branch to the 'membrana nictitans/ and then takes a 
singular course. Some ramifications go to4he frontal 
sinuses and the foramina, and, piercing the orbit of 
the eye for this purpose, present a beautiful view in 
young animals, particularly the sheep. The main 
branch .then enters the cranium again through the 
internal orbital foramen, passes under the dura mater, 
returns through the cribriform plate, and ramifies on 
the membrane of the nose, sending some branches as 
low as the false nostril and alae. 

'' The superior maxillary nerve, or second branch of 
the trigeminus, contains little that is peculiar to or 
has a practical tendency in quadrupeds. The different 
situation and conformation of the bones of the face 
cause the principal or only variation in the distribu- 
tion of this branch in the biped and the quadruped. 
It leaves the cranium through the foramen rotundum, 
and at the base of the skull gives off small ramifica- 
tions to the inner canthus of the eye, the antrum, and 
the two posterior grinder teeth. It also supplies the 
lateral portion of the nasal cavity through the spheno- 
palatine foramen, while filaments are given off from 
the origin of the trunk to the temporal muscle. A 
branch also runs along the upper border of the septum 
nasi to the palate, and a larger branch, which trav- 
erses the palate in company with its blood-vessels, 
passes through the foramen incisivum to the upper 
lip. The main trunk of the nerve now enters into the 
superior and exterior foramen, in the hiatus between 
the palatine bone and the tuberosity of the superior 
maxillary bone, leading into a bony canal (easily traced 
in the horse) between the maxillary sinus and the an- 
trum, and appearing as a great pillar passing tlirough 
the palatine sinuses in the ox. It traverses this canal, 



THE GOOSE'S FOOT. 223 

and at length emerges on the face through the fora- 
men infra-orbitariiim, and under the levator labii supe- 
rioris muscle. It no sooner escapes from this canal 
than it forms the ^pes anserinus' (the goose's foot, for 
it divides something like the foot of this bird). It 
anastomoses with or receives numerous branches from 
the seventh pair, and forms an intricate plexus abt)ut 
the lower part of the face and muzzle. The nerves, 
however, are wisely and beautifully interwoven, for the 
lips, being the seat of touch, require all the flexibility 
and more than the sensibility of the human hand. 

"The inferior maxillary nerve, or third branch of 
the trigeminus, emerges from tlie cranium through 
the foramen lacerum basis crauii, and very soon gives 
o^ four important branches. The first branch, reck- 
oning posteriorly, proceeds backward below the con- 
dyle of the jaw, whore it divides into two portions. 
The first runs up to the parotid gland, ramifies into 
many filaments, and unites with the seventh pair. It 
dips deep into and principally supplies the temporal 
muscle, and penetrates and is distributed through the 
masseter muscle. In this division there seems to be 
concentrated the greater part of the motor fibrils of 
the trigeminus, for these are muscles of extensive and 
powerful action. There are few muscles of the frame 
that are oftener or more powerfully employed than 
those concerned in mastication ; but with the motor 
fibrils those of sensation are doubtless conjoined. 

''The second branch is a long and slender one. It 
first dips into the pterygoideus muscle, which is sup- 
plied by it; consequently it is here also a motor as well 
as a sensitive nerve. It then passes around or behind 
the tuberosity of the upper jaw, supplying the bucci- 
nator muscle — possibly witli sensitive fibrils alone, for 



224 THE FIFTH PAIR OF KERVES. 

others go to this muscle from the seventh pair. In 
the buccinator these fibrils are usually lost; but some- 
times a few of them may be traced to the lower lip. 

'' The third branch, in the order of its being given 
off, is the dental nerve. This is generally considered 
the continuation of the trunk of the inferior maxillary 
nerve. It passes across the pterygoideus and enters a 
canal (the dental canal), on the inner face of the lower 
jawbone, near the upper edge, and at the bending or 
angle of the jaw. It takes its course along the interior 
of the bone (the canal), close to the roots of the teeth, 
and sends out filaments to each of them. Emerging 
through the lower maxillary foramen, it divides into 
two branches, one of which is distributed in numerous 
ramifications on the outside of the lower lip, and the 
other in fewer ramifications on the inside. These are 
evidently sensitive fibrils, the power of motion being 
derived from the seventh pair of nerves. 

" The fourth branch in point of order, but which 
does not enter the 'dental canal,' is the gustatory or 
lingual 7ierve, the largest of the four. It is singularly 
flat, like a little ribbon. It runs along the inside of 
the lower jaw, and a branch of it enters a foramen in 
the jaw to supply the roots of the incisor teeth ; but 
the main nerve, proceeding obliquely downward, gives 
fibrils to the submaxillary glands, and to i\\Q glands 
and muscles at the base of the mouth generally. These 
fibrils form true plexuses about the salivary glands and 
the mnscles of the tongue. They anastomose freely 
with the twelfth pair (the lingnales or motor nerve of 
the tongue), as the twelfth had already done with the 
seventh (the 'portio dura'). The gustatory branch 
penetrates the substance of the tongue between the 
stylo and genio-glossal muscles, passing obliquely to 



RICH PLEXUSES AND LOOPED FILAMENTS. 225 

the surface of the tongue, and terminating in the pa- 
pillag. The papillae, thus endowed with nervous influ- 
ence, are the seat of the sense of taste." 

Of the fifth nerve (in man and in the horse) Prof. 
Owen (quoting partly from Dr. Swan), says (" Odon- 
tography," vol. i, pp. Ixv-vi) : ' 

"The nerves of the teeth are derived from the tri- 
geminal, or fifth pair, of which the second division sup- 
plies those of the upper Jaw, the third division those 
of the lower. In the human subject, the three dental 
branches of the infra-orbital nerve intercommunicate 
by their primary branches, from which, and from a 
rich plexus formed by secondary branches upon the 
membrane lining the antrum, two sets of nerves are 
sent off to the alveolar processes of the upper jaw; one 
set {rami dentales) supplies the teeth, the other {rami 
gingivales) the osseous tissue of the gums. The latter 
agree in number with the intervals of the teeth, as the 
proper dental nerves do with the teeth themselves. 
These two sets are not, however, so distinct but that 
some intercommunications are established between the 
fine branches sent off in their progress to the parts 
they are specially destined to supply. The rami den- 
tales take the more direct course (through the middle 
part of the osseous tissue to the teeth) penetrate the 
orifices of the fangs, and form a rich plexus with 
rhomboidal meshes upon the coronal surface of the 
pulp, the peripheral elementary filaments returning 
into the plexus by loops. In the lower jaw the dental 
nerve, besides supplying the proper nerves to the teeth, 
also forms a rich plexus, in which it is joined by some 
branches from the division of the nerve that afterward 
escapes by the foramen mentale, and from this plexus 



226 THE FIFTH PAIE OF ITERVES. 

the cancellous tissue of the bone and the vascular 
gums are supplied. * * * * 

" In the horse the maxillary plexus is most devel- 
oped above and between the alveoli of the three pre- 
molar teeth. It is less complex where it supplies the 
molar teeth, their alveoli, and the gums. In the 
lower jaw of the horse a very rich plexus begins to be 
formed in the cancellous substance of the bone by 
branches of the dental nerve, soon after its entry into 
the canal." 



VOCABULARY. 



Note, — The definitions, wliere not otherwise credited, are 
from " Dunglison's Medical Dictionary." 

A. 

Ala (plural, alae). A term often used by anatomists for parts 
which project like a wing from the median line; as the alae 
nasi, alsB of the uterus, &c. 

Albu^men (wliite). An immediate principle of animals and veg- 
etables, which constitutes the chief part of the white of egg. 
It is found in the serum, chyle, synovia, serous fluids, &c. 
There is not much difference in chemical composition be- 
tween animal and vep:etable albumen, fibrin, and casein. 
Fibrin alona appears, however, to be possessed of plastic 
properties. Also the white (sclerotic) of the eye. 

Alve'olar Arches are formed by the margins or borders of 
tlie two jaws, which are hollowed by the rJveoli. 

Alveolar Artery, arises from the internal maxillary, de- 
scends beliind the tuberosity of the upper jaw, and gives 
branches to the up]x;r molar teeth, gums, periosteum, mem- 
brane of the maxillary sinus, and buccinator muscle. 

Alveolar BORDEPt. The part of the jaws that is hollowed by 
the alveoli. 

Alveolar Membranes are very fine membranes, situated be- 
tween the teeth and alveoli, and formed by a portion of the 
sac wliich incloses the tooth before it pierces the gum. By 
some this membrane has been called the ' alveolo-dental 
periosteum.' 

Alveolar Vein. This has a distribution similar to the artery. 



228 TOCABULARY, 

ALVE'oiiTTS (pi. alveoli). The alveoli are the sockets of tlie 
teeth, into which they are, as it were, driven. Their size 
and shape are determined by the teeth which they receive, 
and they are pierced at the apex by small holes wliich give 
passage to the dental vessels and nerves. 

Anastomo'sis (* a mouth '). Communication between two ves- 
sels. By considering the nerves to be channels, in which a 
nervous fluid circulates, their communication likewise has 
been called anastomosis. By means of anastomoses, if the 
course of a fluid be arrested in one vessel, it can proceed 
along others, 

Anisodac'tyle. Hoofed quadrupeds with toes (on the hind- 
feet at least) in uneven numbers, as one, three, or five, the 
latter being manifested by the Proboscidians. All these have 
a simple stomach and an enormous coecum. Examples : 
Horse, ^apir, rhinoceros, elephant. R. Owen. 

Ante'bioh (from ante, ' before '). Situate before. Great con- 
fusion has prevailed with anatomists in the use of the terms 
before, behind, &c. Generally, the word anterior is applied 
to parts situate before the median line, the body being in the 
erect posture, with the face and palms of the hands turned 
forward, and the feet applied longitudinally together. 

Antrum. A cavern. A name given to certain cavities in 
bones, the entrance to v/hich is smaller than the bottom. 

Antrum op Highmore. A deep cavity in the substance of the 
superior maxillary bone, communicating with the middle 
meatus of the nose. It is lined by a prolongation of the 
Schneiderian membrane. 

Arach'noid Membrane. A name given to several mem- 
branes, v/hicli, by their extreme thinness, resemble spider- 
webs. The moderns use it for one of the membranes of the 
brain, situate between the dura mater and pia mater. It is a 
serous membrane, composed of two layers, the external being 
confounded, in the greater part of its extent, witli the dura 
mater, and, like it, lining the interior of the cranium and spi- 
nal canal ; the other is extended over the brain, from which 
it is separated by the pia mater, without passing into the 
sinuosities between the convolutions, and penetrating into 
the interior of the brain by an opening at its posterior part, 
under the ' corpus callosum.' It forms a part of the investing 



VOCABULARY. 229 

sheath of nerves, as they pass from the encephalic cavities. 
Its chief uses seem to be to envelop and, in some measure, 
protect the brain, and to secrete a fluid for the purpose of 
keeping- it in a state best adapted for the performance of its 
functions. 
• AitE'OLA. A diminutive of 'area.' Anatomists understand by 
areola? the interstices between the fibers composing organs, 
or those existing between laminae, or between vessels which 
interlace with each other. 
Aegen'ti Nitras. Nitrate of silver ; lunar caustic. The vir- 
tues of nitrate of silver are tonic and escharotic. It is given 
in chorea, epilepsy, &c.; locally, it is used in various cases as 
an escharotic. Dose, gr. 1-8 to gr. 1-4, in pill, three times 
a day. 
Armadil'lo. (So called from being protected or armed by a 
scaly covering like the plate armor of the middle ages.) A 
genus of South American quadrupeds, belonging to the order 
of edentata, and characterized by a defensive armor of small 
bony plates, covering the head and trunk, and sometimes the 
tail. Br ancle. 

AnTicuL ACTION. The union of bones with each other, as well 
as the kind of union. Articulations are generally divided 
into two kinds — movable and immovable. The articulations 
, are subject to a number of diseases, which are generally some- 
what severe; they may be physical, as wounds, sprains, lux- 
ations, &c., or they may be organic, as ankylosis, extraneous 
bodies, caries, rheumatism, gout, &c. 
At'rophy. Progressive and morbid diminution in the bulk of 
the whole body or of a part. Atrophy is generally sym|> 
tomatic. Any tissue or organ thus affected is said to be 
' atrophied.' 
AuRic'uLAR. (The ear.) That which belongs to the ear, espe- 
cially the external car. 

B. 

Batra'chia. An order of reptiles including toads, frogs, and 

salamanders. Brande. 

One of the five classes into which the vertebrate animals 

are usually divided, though some writers have reduced the 

class to the rank of an order of reptiles, a class with which 



230 VOCABULARY. 

they are popularly confounded. The batrachians are cold- 
blooded and oviparous, and in most living- species are with- 
out scales, and the blood is partly aerated through the skin. 
The young, for the most part, breathe by gills like those of 
fishes; they assume a fish-like form (as the tadpole), and 
finally, when adult, with few exceptions, loss their gills and 
breathe by lungs, like true or scaly reptiles. They generally 
have limbs, but not always. Johnson's JSF. U. Oyc. 

Bi'furcation. (A fork.) Division of a trunk into two 
branches, as the bifurcation of the trachea, aorta, &c. 

Buccal. That which concerns the mouth, and especially the 
cheek. 

C. 

Cjecum. The blind gut ; so called from its being perforated at 
one end only. That portion of the intestinal canal which is 
seated between the termination of the ileum and beginning 
of the colon, and which fills, almost wholly, the right iliac 
fossa, where the peritoneum retains it immovably. Its length 
is about three or four fingers' breadth. The ileo-ccecal valve, 
or valve of Bauhin, shuts oflT all communication between it 
and the ileum, and the 'Appendix vermiformis cseci' is at- 
tached to it. 

In the horse the csecum (water stomach) will hold four gal- 
lons. A horse will drink at one time a great deal more than 
his stomach will contain ; but even if he drinks a less quan- 
tity, it remains, not in the stomach or small intestines, but 
passes to the csecum, and is there retained, as in a reservoir, 
to supply the wants of the system. Youatt. 

Cal'culus. a diminutive of ' calx,' a iime-stone. Calculi are 
concretions, which may form in every part of the animal 
body, but are most frequently found in the organs that act 
as reservoirs, and in the excretory canals. They are met 
with in the tonsils, joints, biliary ducts, digestive passages, 
lachrymal ducts, mamma?, pancreas, pineal gland, prostate, 
lungs, salivary, spermatic, and urinary passages, and in the 
uterus. The causes which give rise to them are obscure. 
Those that occur in reservoirs or ducts are supposed to be 
owing to the deposition of the substances, which compose 
them, from the fluid as it passes along the duct ; those which 
occur in the substance of an organ are regarded as the pro- 



VOCABULARY* 231 

duct of some clironic irritation. Their general effect is to 
irritate, as extraneous bodies, the parts with wliich they are 
iu contact, and to produce retention of the fluid wlience they 
have been formed. The symptoms differ, according to the 
■ Sensibility of tlio organ and the importance of the particular 
I secretion whose discharge they impede. Their 'solution' is 
i generally impracticable. Spontaneous expulsion or extrac- 
tion is the only way of getting rid of them. 
Cancel'li. ' Lattice- work,* The cellular or spongy texture of 
bone, consisting of numerous cells, communicating with each 
other.' They contain a fatty matter, analogous to marrow. 
This texture is met with principally at the extremities of 
long bones, and some of the short bones consist almost wholly 
of it. It allows of the expansion of the extremities of bones, 
without adding to their weight, and deadens concussions. 
Can'dla. Diminutive of canna, ' a reed.' A small tube of gold, 
silver, platinum, iron, lead, wood, elastic gum, or gutta- 
percha, used for various purposes in surgery. 
Cap'illahy (from cajnllus, ' a hair ')• Hair-like ; small. 
Capillary Vessels are the extreme radicles of tlie arteries 
and veins, which together constitute the capillary, interme- 
diate, or peripheral vascular system— the methce'mata blood 
channels of Dr. Marshall Hall (that is, the system of vessels 
in which the blood undergoes the change from venous to 
arterial, and conversely). They possess an action distinct 
from that of the heart. 
Carries. An ulceration of bone—' necrosis' being the death of 
a bone. It resembles the gangrene of soft parts. It is recog- 
nized by the swelling of the bone which precedes and accora- 
! panics it ; by the abscesses it occasions ; the fistulre which 
; form ; the sanious character, peculiar odor, and quantity of 
the suppuration, and by the evidence afforded by probing. 
The most common causes of caries are blows, the action of 
some virus, and morbid diathesis. When dependent on any 
virus in the system, this must be combated by appropriate 
remedies. When entirely local, it must be converted, where 
practicable, into a state of necrosis, or death of the affected 
part. To this end apply stimulants, tlif^ actual cautery, &c. 
Cahot'ids. The great arteries of the neck, vv'hich carry blood 
to the head. 



232 VOCABULARY. 

Car'tilage. a solid part of the animal body, of a consistence 
between bone and ligament, wliicli in the fetus is a substi- 
tute for bone, but in the adult exists only in the joints, at 
the extremities of the ribs, «&c. 

Cer'vical. Everything which concerns the neck, especially 
the back part. 

Ciievrotain'. a species of the geuus Moschus, related to the 
deer, but having no horns, and otherwise peculiar. It is 
small, light, and graceful, and lives in the mountains of Asia, 
from the Altai to Java. Dana. 

Choroid Membrane. A thin membrane, of a very dark color, 
which lines the sclerotic internally. It is situate between the 
sclerotic and retina, has an opening posteriorly for the pas- 
sage of the optic nerve, and terminates anteriorly at the great 
circumference of the iris, where it is continuous with the cili- 
ary processes. The internal surface is covered with a dark 
pigment, consisting of several layers of pigment cells. Its 
use seems to be to absorb the rays of light after they have 
traversed the retina. 

Cil'iary. Relating to the eyelashes, or to cilia. This epithet 
has also been applied to different parts, which enter into the 
structure of the eye, from the resemblance between some of 
them (the ciliary processes) and the eyelashes. 

Colon. That portion of the large intestines which, extends 
from the caecum to the rectum. The colon is usually divided 
into four portions. 1. The right lumbar or ascending colon, 
situate in the right lumbar region, and beginning at the 
C33cum. 2. The transverse colon — transverse arch of the 
colon — the portion which crosses from the right to the left 
side, at the upper part of the abdomen. 3. The left lumbar 
or descending colon, extending from the left part of the trans- 
verse arch, opposite the outer portion of the left kidney, to 
the corresponding iliac fossa. . 4. The iliac colon, or sigmoid 
flexure of the colon ; the portion which makes a double cur- 
vature in the left iliac fossa, and ends in the rectum. 

In the horse the colon is exceedingly large, and is capable 
of containing no less than twelve gallons of liquid or pulpy 
food. It is of considerable length ; completely traversing the 
diameter of the abdominal cavity, it is then reflected upon 
itself, and retraverses the same space. Touatt. 



VOCABULARY. 233 

Com'missures, The point of union between two parts ; thus 

the commissures of the eyelids, lips, &c., are the angles which 

they form at the place of union. 

Comparative Anat'omy. The science which treats of the 

structure and relation of organs in the various branches of 

. the animal kingdom, without a knowledge of which it is im- 

) possible to understand the beautifully progressive develop- 
ment of organization, necessary even for the full comprehen- 
sion of the uses of many parts of the human body, which, 
apparently rudimentary and useless in man, are highly de- 
veloped in other animals. This science is also the basis of 
physiology and the natural classification of animals. 

American Cyclopedia. 

Con'dyle. An articular eminence, round in one direction, flat 
in the other. A kind of process, met with more particularly 
in the ginglymoid joints, such as the condyles of the occipi- 
tal, inferior maxillary bone, &c. 

Congen'ital (from con and genitus, 'begotten'). Diseases 
which infants have at birth; hence, congenital allectionsare 
those that depend on faulty conformation, as congenital her- 
nia, congenital cataract, &c. 

CoNJUNCTi'vA Membra' xa. A mucous membrane, so called 
because it unites the globe of the eye Avith the eyelids. It 
covers the anterior surface of the eye, the inner surface of the 
eyelids, and the 'caruncula lachry malis. ' It possesses great 
general sensibility, communicated to it by the fifth pair of 
nerves. 

Copyba'ra is the largest known quadruped of the order Ro- 
dentia, and belongs to the family Cavidss. It is an aquatic 
animal, a native of South America, and feeds on vegetable 
food exclusively. Its dentition resembles that ofthecavy, 
except that the grinding teeth are formed of many trans- 
verse plates, the number of plates increasing as the animal 
advances in age. It is inoffensive and easily tamed. The 
flesh is esteemed good food. It is somewhat smaller than 
the common hog. Johnson's New Unicersal Cyclopedia. 

Cokpus'cle A minute particle or physical atom; one of the 
very small bodies which compose large bodies, not the ele- 
mentary principles of matter, but such small particles, simple 
or compound, as arc not dissolved or dissipated by ordinary 



234 VOCABULARY. 

heat. An animal cell, or cellular anatomical element, as a 
blood corpuscle ; a lymph corpuscle. Webster. 

Coreela'tion (mutual relation) OF Fokces (otherwise called 
'Transmutation of Force or Energy'). A phrase of recent 
origin, employed to express the theory' that any one of the 
various forms of physical force may bo converted into one or 
more of the other forms. The cardinal point in this theory 
is the doctrine of heat and its relation to other agents, espe- 
cially to mechanical motion. For example, the heat mani- 
fesred when we rub two fiat surfaces briskly against each 
other, is only our own muscular motion checked by the fric- 
tion, and changed thereby into the heat which the surfaces 
reveal. On the other hand, this muscular motion is only the 
heat of our bodily frame expending itself in this way. In 
either case the energy has hot been annihilated, but only 
transferred, and appears in a nevv^ form. 

Johnson's N. IT. Cyc, article revised by J. H. Seelye. 

Crura. The plural of cms, ' a leg.' Applied to some parts of 
the body, from their resemblance to legs or roots, as the 
' crura cerebri,' ' crura cerebelli,' &c. 

Cul-de-sac. Any bag-shaped cavity, tubular vessel, or organ, 
open only at one end. Dana. 

I>. 

Dental Canal. The bony canals through which the vessels 

and nerves pass to the interior of the teeth. 
Dental Cavity. A cavity in the interior of the teeth, in which 

is situate the dental pulp. (More properly the pulpal cavity.) 
Dental Pulp. The pultaceous substance, of a reddish-gray 

color, very soft and sensible, which fills the cavity of the 

teeth. It is well supplied w^ith capillary vessels. 
Dentig'erous. Tooth-carrying, as dentigerous cysts ; one 

containing teeth. 
Dermal. Relating or belonging to the skin. 
Dermatoid or Dermoid. That which is similar to the skin. 

This name is given to different tissues which resemble the 

skin. The dura mater has been so called by some. 
Deter'gents. Medicines which possess the power to deterge 

or cleanse parts, as wounds, ulcers, &c. They belong to the 

class of stimulants, or to that of emollients. 



VOCABULARY. 235 

Diabe'tes. a disease cbaracterized by great augmentation and 
often manifest alteration in the secretion of urine, with ex- 
cessive thirst and progressive emaciation. The quantity of 
urine discharged in 24 hours is sometimes 30 pints and up- 
ward, each pint containing 3| ounces saccharine matter. 

Dl'APiinAGM. 1. A dividing membrane or thin partition, com- 
monly with an opening through it. 2. The muscle separa- 
ting the chest or thorax from the abdomen or lower bellv ; 
the midriff. Webntei: 

Diath'esis. Disposition, constitution, affection of the body ; 
predisposition to certain diseases rather than to others. The 
principal diatheses mentioned by authors are the cancerous, 
scrofulous, scorbutic (pertaining to scurvy), rheumatic, gouty, 
and calculous. 

DicnOT'oiious. Regularly divided by pairs, from top to bot- 
tom ; as, a dicliotomous stem. Martyn. 

DiVERTic'uLTJ^r. A blind tube branching out Crom the course 
of a larger one. An organ which is capable of receiving an 
imusual quantity of blood, when the circulation is obstructed 
or modified elsewhere, is said to act as a diverticulum. Also 
a malformation or diseased appearance of a part, in which it 
passes out of its regular course. It is sometimes applied to 
such a condition of the alimentary canal. Also a hole to get 
out at. A by- passage. 

Dugong'. a herbivorous, cetaceous animal of the Indian Ocean, 
with a tapering body ending in a crescent-shaped fin. The 
fabled mermaid seems to have been founded on the dugong. 

Gilbert. Brande, 
It is generally from eight to twelve feet long, though it is 
said to sometimes attain the length of twenty-five feet. The 
upper lip is thick and fleshy, and forms a kind of snout ; the 
upper jav/ bonds downward almost to a right angle ; the 
eyes are very small, with a nictitating membrane ; the skin 
is thick and smooth. Its flesh is said to resemble beef, and 

. is prized as food. The oil is recommended as a substitute for 
cod -liver oil. Johnson' .s JV. U. Cyc. 

DuKA Matek, a fibrous, semi-transparent membrane, of a 
pearly-white color, thick and very resisting ; lines the cavity 
of the cranium, and contains the spinal marrow ; protects the 
brain and marrow, and by its various expansions — the falx 



236 VOCABULARY. 

cerebri, tentorium, &c. — supplies tlie different parts of tlie 
cerebral mass. 

E. 

Econ'omy. By the term 'animal economy' is understood the 
aggregate of the laws wliicli govern the organism. The word 
economy is also used for the aggregate of parts which con- 
stitute man or animals. 

Edenta'ta. In natural history, an order of animals that are 
destitute of front teeth, as the armadillo and ant-eater. Bell. 

Eden'tulus. One without teeth. 

Em'bryo. The fecundated germ, in the early stages of its de- 
velopment in utero. At a certain i)eriod of its increase, the 
name 'fetus' is given to it, but at what period is not deter- 
mined. Generally, the embryo state is considered to extend 
to the perio.l of quickening. 

Encephali'tis. This term has been used by some nosologists 
(classifiers of diseases) synonymously with ' cephalitis ' and 
'phrenitis.' By others it has been appropriated to inflam- 
mation of the brain, in contradistinction to that of the mem- 
branes. 

E'OCENE. In geology, a term applied to the earlier tertiary de- 
posits, in which are a few organic remains of existing species 
of animals. Hence the term eocene (recent), which denotes 
the dawn of the existing state of things. 

Dana. Lyell. Mantell. 
In America the eocene strata contain numerous fossils, 
mostly marine moUusks, but also include some gigantic ver- 
tebrates, a carnivorous cetacean seventy foet in length, and a 
shark of which the teeth are sometimes six inches in length. 
The Wyoming beds have furnished the remains of a remark- 
able group of mammals, which are thought by. Prof. Marsh 
to form a new order, and which he has named ' Dinocerata.' 
The largest of these (Dinoceras mirabilis) had the bulk of an 
elephant, and was provided with three pairs of horns and a 
pair of great saber-like canine teeth. JoJin son's K U. Cyc. 

Epider'mis. a transparent, dry, thin membrane, devoid of 
nerves and vessels, which covers all the surface of the body, 
except the parts that correspond to the nails. It appears to 
consist of minute scales placed one above the other. The 
epidermic system, in general anatomy, comprises three parts. 



VOCABULARY. 237 

1, External epidermis. 2. Epidermis spread over the mu- 
cous membranes. 3. The nails and liair. 
Epithe'lium. Tiie thin layer of ei)idermis wliich covers parts 
deprived of derma, properly so called, as the nipple, mucous 
membranes, Jips, &c. 
Eschar. A slougli, crust, or scab. 

Escharot'ic. Any substance whicli, when applied upon a liv- 
incT part, gives vise to an eschar, such as caustic potassa, con- 
centrated mineral acids, «Sic. 
Esoph'agus, The gullet. A musculo-membranous canal, 
extending from the inferior extremity of the pharynx to the 
upper oritice of the stomach. 
Ethmoid. Shaped like a sieve. 

Ethmoid Bo.ne. One of the eight bones which compose the 
cranium, so called because its upper plate is pierced by a con- 
siderable number of holes. It is situate at the anterior, in- 
ferior, and middle part of the cranium. 
Evolu'tion. According to the hypothesis of evolution, in its 
simplest form, the universe as it now exists is the result of 
" an immense series of changes," related to and dependent 
upon each other, as successive steps, or rather growths, con- 
stituting a progress ; analoorous to the unfolding or evolving 
of the parts of a living organism. Evolution is defined by 
Herbert Spencer as consisting in a progress from the homo- 
geneous to the heterogeneous, from general to special, from 
the simple to the complex ; and this process is considered to 
be traceable in the formation of the worlds in space, in the 
multiplication of the types and species of plants and animals 
on the globe, in the origination and diversity of languages, 
literature, arts, and sciences, and in all the changes of human 
institutions and society. Hrnry Ilartsliorne. 

The animal kingdom displays a unity of plan or a correla- 
tion of parts by which common principles are traced through 
the most disguising diversities of form, so that in aspect, struc- 
ture, and functions the various tribes of anim:ils pass into 
each other hy sliffht and gradual transitions. The arm of a 
man, the fore limb of a qnndruncd, the wing of a bird, and 
the fin of a fish are homologous, that is. they rontnin the 
same essential parts, modified in correspondence with the dif- 
ferent circumstances of the animal ; and so with the other 



238 VOCABULARY. 

organs. Prof. Cope says : " Every individual of every species 
of a given branch of the animal king-dom is composed of ele- 
ments common to all, and the differtsuces whicli are so radi- 
cal in the higher grades are but the modifications of the same 
elemental parts." E. L. Youmans. 

Exfolia'tion (from ex s^ndi folium, ' a leaf). By this is meant 
the separatio2i of the dead portions of a bone, tendon, apon- 
eurosis (a white shining membrane), or cartilage, under the 
form of himellee (small scales). Exfoliation is accomplished 
by the instinctive action of the parts, and its object is to de- 
tach the dead portions from those subjacent, which are still 
^ alive. For this purpose the latter throw out fleshy granula- 
tions, and a more or less abundant suppuration occurs, which 
tends to separate the exfoliated part — now become an extra- 
neous body. 

ExosTo'sis. An osseous tumor, which forms at the surface of 
bones, or in their cavities. 

Exostosis Dentium. Exostosis of the teeth. 

F. 

Ferhu'ginous (chalyb'eate). Of or belonging to iron ; contain- 
ing iron. Any medicine into which iron enters, as chalyb- 
eate mixture, pills, waters, &c. 

Fe'tus. See ' embryo.' 

Fiber. An organic filament, of a solid consistence, and more or 
less extensible, wliich enters into the composition of every 
animal and vegetable texture. 

Fil'ament. a thread. This word is used synonymously with 
fibril ; thus we say a nervous or cellular filament or fibril. 

Fis'tula. ' A pipe or reed.' A solution of continuity (a division 
of parts previously continuous) of greater or less depth and 
sinuosity, the opening of which is narrow, and the disease 
kept up by an altered texture of parts, so that it is not dis- 
posed to heal. A fistula is ' incomplete ' or ' blind' when it 
has but one opening, and ' complete ' when there are two, the 
one communicating with an internal cavity, the other exter- 
nally. It, is "lined in its whole course by a membrane which 
seems analogous to mucous membranes. 

Fol'licle. a follicle or crypt is a small, roundish, hollow 
body, situate in the substance of the skin or mucous mem- 
branes, and constantly pouring the fluid which it secretes on 



VOCABULARY. 239 

their surfaces. Tlie use of the secretion is to keep the parts 
on which it is poured supple and moist, and to preserve them 
from the action of irritating bodies with which they have to 
come in contact. 

Foka'men. Any cavity pierced through and through. Also 
the orifice to a canal. 

Fossa. A cavity of greater or less depth, the entrance to which 
is always larger than the base. 

FRiENUM. A small bridle. A name given to several membran- 
ous folds, which bridle and retain certain organs. 

Frontal Bone. A double bone in the fetus, single m the adult, 
i situate at the base of the cranium, and at the superior part 
of the face. 

Function. The action of an organ or system of organs. Any 
act necessary for accomplishing a vital phenomenon. A 
function is a special oflace in the animal economy, which has 
as its instrument an organ or apparatus of organs. 

Fungus. The mushroom order of plants. In pathology the 
word is commonly used synonymoasly with fungosity (my- 
cosis). 

Fungus H^mato'des (Hacmatodes Fungus). An exceedingly 
alarming carcinomatous (cancerous) affection, which was fii'st 
described with accuracy by Mr. Jolui Burns, of Glasgow. It 
consists in the development of cancerous tumors, in which 
the inflammation is accompanied with violent heat and pain, 
and with fungus and bleeding excrescences. 

G. 

Gang'lion. Nervous ganglions are enlargements or knots in 
the course of a nerve. 

Gastric. Belonging or relating to the stomach. 

Gastric Juice. A fluid secreted from the mucous membrane 
of the stomach.- It assists digestion. 

Gentian Wine (vinura gentians compositnm, or wine bitters). 
'Gentiana Lutea' is the systematic name of the officinal 
gentian. The plant is common in the mountains of Europe. 
The root is almost inodorous, extremely bitter, and yields 
its \irtues to ether, alcohol, and water. It is tonic and 
stomacliic, and, in large doses, aperient. It is most fre- 
quently, however, used in infusion or tincture. 



240 VOCABULAET. 

Geol'ogt is that branch of natural science which treats of the 
structure of the crust of the earth and the mode of formation 
of its rocks, together with the history of physical changes 
and of life on our planet during the successive stages of its 
history. It has been inferred that its actual crust must be 
very thick, perhaps not less than 2,500 miles. Geology de- 
pends upon mineralogy for its knowledge of the constituents 
of rocks, and upon chemistry and physics for its knowledge 
of the laws of change ; and in its study of fossil remains it is 
closely connected with the sciences of zoology and botany. 
A knowledge of geology lies at the base of physical geogra- 
phy, and is essential to the skillful prosecution of minini^ 
and other useful arts. ^ J. W. Dawson. 

The facts proved by geology are that during an immense 
but unknown period the surface of the earth has undergone 
successive changes ; land has sunk beneath the ocean, while 
fresh land has risen up from it ; mountain chains have been 
elevated ; islands have been formed into continents, and con- 
tinents submerged till they have become islands ; and these 
changes have taken place, not once merely, but perhaps 
hLuulrcds, perhaps thousands of times. A. L. Wallace. 

Prof. Dana says the " earth was first a featureless globe of 
fire ; then had its oceans and dry land ; in course of time re- 
ceived mountains and rivers, and finally all those diversities 
of surface which now characterize it." 

Gland. (An acorn ; a kernel.) Softish, g^ranular, lobated or- 
gans, composed of vessels and a particular texture, which 
draw from the blood the molecules necessary for the forma- 
tion of new fluids, conveying them externally by means of 
one or more excretory ducts. Each gland has an organiza- 
tion peculiar to it, but we know not the intimate nature of 
the glandular texture. 

Guana'co. The ' Auchenia Huanaca,' a species of the genus of 
ruminant mammals to which the llama belongs. It inhabits 
the Andes, and is domesticated. It is allied to the camel. 

Webster. 

The guanaco is especially abundant in Patagonia and 

Chili, where it forms large flocks. It is about three feet high 

at the shoulders, and is extremely swift. In domestication it 

is ill-tempered, and has a disagreeable habit of ejecting saliva 



VOCABULARY. 241 

upon unwelcome visitors. In its wild state it seldom diiiiks 
water. Its flesh is edible and its skin valuable. 

Johnson's iV. U. Gyc- 
H. 

Haversian Canals. (Canals of Havers, nutritive canals, &c.) 
The canals through which the V(issel3 pass to the bones. 
They are lined by a very line lamina of compact texture, or 
are formed in the texture itself. There is generally one large 
nutritious canal in a long bone, situate toward its middle. 

Hia'tus. xV foramen or aperture. Mouth. The vulva. Also 
yawning. 

Histol'ogy is the branch of anatomy which treats of the minute 
structure of the tissues of which living beings are composed. 
It is divided into ' human histology,' which treats of the tis- 
sues of man ; ' comparative histology,' which treats of the tis- 
sues of the lowor animals, and ' vegetable histology,' which 
treats of the tissues of plants. Each of these divisions may 
be subdivided into 'normal' and 'pathological' histology, 
the first referring to the healthy tissues, the second investi- 
gating the changes they undergo in disease. J. J. Vioodicard. 

Hoove. A disease in cattle, consisting in the excessive inflation 
of the stomach by gas, ordinarily caused by eating too much 
green food. Gardner. 

Hyper' TROPnY. The state of a part in which the nutrition is 
performed with greater activity, and which on that account 
at length acquires unusual bulk. The part thus aflected is 
said to be hypertrophied or hypertrophous. 

I. 

Infiltr ACTION. To filter; effusion. The accumulation of a 
fluid in the areolae of a texture, and particularly in (he areo- 
lar membrane. The fluid eff'used is ordinarily the 'liquor 
sanguinis,' sound or altered ; sometimes blood or pus, faeces 
or urine. When infiltration of a serous fluid is general, it 
constitutes 'anasarca' (droj)sy) ; when local, ' oedema.' 

Intersti'tial. Applied to that which occurs in the interstices 
of an organ, as interstitial absorption, interstitial pregnancy, 
&t;. (See ' Suppuration.') 

Intra-uterine. {lutri, 'within.,' uterus, 'the womb.') That 
which takes place within the womb, as intra-uterine life. 
11 



24,2 VOCABULARY. 

Iris. So called from its resembling the rainbow in a variety of 
colors. A membrane, stretclied vertically at the anterior 
part of the eye, in the midst of the aqueous humor, in which 
it forms a iiini of circular, flat partition, separating the an- 
terior from the posterior chamber. It is perforated by a cir- 
cular opening called the pupil, which is constantly varying 
its dimensions, ovv^ing to the contractions of the fibers of the 
iris. 

Isodac'tyle. Hoofed quadrupeds with toes in even number, as 
two or four, and which have a more or less complicated 
stomach, with a moderate-sized, simple caecum. Examples: 
Ox, hog, peccary, hippopotamus. 11. Owen. 

Li. 

Lach'hymal. Belonging to the tears. This epithet is given 
to various parts. 

Lacuna of Bone. Certain dark, stellate spots, with thread- 
like lines radiating from them, seen under a high magnifying 
power. These were first believed to be solid (jEseous cor- 
puscles or cells (corpuscles of Purkinje), but are now re- 
garded as excavations in the bone, with minute tubes or 
canalic'uli proceeding from them and commmiicating with 
the Haversian canals. The lacunse and canaliculi are fibers 
concentrated in the transit of nutrient fluid through the osse- 
ous tissue. 

Lam'iNA. a thin, flat part of a bone ; a plate or table, as the 
cribriform lamina or plate of the ethmoid bone. Lamina and 
lamella are generally used synonymously, although the latter 
is properly a diminutive of the former. 

Lesio T. Derangement, djsorder; any morbid change, either in 
the exercise of functions or in the texture of organs. ' Or- 
ganic legion ' is synonymous with organic disease. 

Lipo'ma. a fatty tmnor of an encysted or other character. 

LiPOiNi^ATOUS. Having the nature of lipoma, as a lipomatous 
ra ass. 

LiQTjOU Sang'uinis. a term given by Dr. B. Babington to one 
of the constituents of the blood, the other being the red par- 
ticles. It is the eft\rsed material (called yd^sma, coagulable 
or plastic lymph, intercellular fluid, &c.), from which the cells 
obtain the constituents of the different tissues and secretions. 



VOCABULARY. 243 



M. 



Malar. Beloncrlng to tlic clisek, as tlie malar bone. 

Malar Process. Z/goniatic process. (Cheek bone process.) 

Masseter, a muscle situate at tlio posterior part of the cheek, 
and lying upon the ramus ot the lower jawbone. Its office is 
to raise the lower jaw and to act in mastication. 

Mas'todon. An extinct genus of quadru[>eds. When alive it 
must have been twelve or thirteen feet high, and, iucluding 
the tusks, a'oout twenty-five feet long. The tusks measui-e 
ten feet eleven inches, about two and a Imlf feet being im- 
planted in the socket. According to Owen, the teeth are 
seven on each side, above and below. The molars have 
wedge-shaped, transverse ridges, the summits of which are 
divided hj a depression lengthwise with the tooth, and sub- 
divided into cones, more or less resembling the teats of a cow. 
In some species there are from three to five ridges to each 
posterior molar; in other species five or more. 0. 0. Marsh. 
(The mastod )u takes its name from the mastoid or nipple- 
like processes of its teeth.) 

Mastoid. Having the form of a nipple. 

Max'illary. Relating or belonging to the jaws. 

Mea'tus. A passage or canal. 

Median Line. A vertical line, suppdSed to divide a body lon- 
gitudinally into two equal j)arts, the one light, the other left. 

Med'ullary. Relating to the marrow, or analogous to marrow. 

MEaATHE'RiU-M. An extinct, genus of Quaternary mammals. 
'Megatherium Cuvieri,' from South America, exceeded the 
rhinoceros in size, its skeleton measuring eighteen feet in 
length. The vertebrae of the tail are very large and |x>wer. 
fnl, and that organ, with tlie lund-legs, seems to have formed 
a support for the heavy body, while X\v^ liiige fore-legs were 
employed in breaking the branches from trees or tearing 
tliem down for food. There are four toes in front and two 
behind. The teeth, five above and four below on each side, 
resemble those of the sloths. They grew from persistent 
pulp", nnl are deeply implantc 1 in the jaws; they have a 
grinding sarfacL^ of triangular ridges, and were fitted for mas- 
ticating coarse vegetable food. 0. C. Marsh. 

Membrank a name given to diffbi-ent thin organs, represent- 



244 VOCABULARY. 

ing" a S]3ecies of supple and more or less elastic webs, varying 
in tlieir structure and vital properties, and intended, in gen- 
eral, to absorb or secrete certain linids, and to separate, en- 
velop, and form other organs. Bicliat has divided the mem- 
branes into siniple and compound. 

Membra'na Nic'titans. The ' haw ' of the horse's eje. It is 
a triangular-shaped cartilage, concealed within the inner cor- 
ner of the eye, and is black or pied. It is used by the horse, 
in lieu of hands, to wipe away dust, insects, &c. The eye 
of the horse has strong mnscle& attached to it, and one, 
peculiar to quadrupeds, by the aid of which the eye may be 
drawn back out of the reach of danger. When this muscle 
acts, the haw, which is guided by the eyelids, shoots across 
the eye with the rapidity of lightning, and thus carries off 
the offending matter. Its return is eqmilly rapid, Youatt. 
(Prof. Youatt denounces the practice of cutting out tlie 
haw as barbarous, that is, in ordinary cases of inflammation. 
Ho says that if farriers and grooms were compelled to walk 
for miles in the dust without being permitted to wipe or 
cleanse their eyes, they would feel the torture to which they 
often subject the horse.) 

Mi'ocEiME. Literally, less recent. In geology, a term applied 
to the middle division of the tertiary strata, containing fewer 
shells of recent species than the Pliocene, but more than the 
Eocene. Lydl. 

The Miocene is apparently the culminating age of the 
mammalia, so far as physical development is concerned, 
which accords with its remarkably genial climate and exu- 
berant vegetation. In Europe the beds of this age present 
for the first time examples of the monkeys. Among carniv- 
orous animals, we have cat-like creatures, one of which is dis- 
tinguished from all modern animals of its group hy the long-, 
saber-shaped canines of its upper jaw, fitting it to pull down 
and destroy those large i^achyderms which could have easily 
shaken off a lion or a tiger. Here also we have the elephants, 
the mastodon, a great, coarsely -built, hog-like elephant, 
^ome species of which had tusks both in the upper and lower 
jaw ; the rhinoceros, the hippopotamus, and the horse, all of 
extinct species. J. W. Bairson. 

MORPnOLOG'iCAL.. That which has relation to the anatomical 



VOCABULARY. 245 

conformation of parts. Applied at times to tlie alterations 
in tlie ' for;n ' of the several parts of the embryo, in contra- 
distiuctioa to ' histological,' which is applied to the transfor- 
mation by which the tismes are gradually generated. In 
comparativa anatomy it is applicvl to the history of the modi- 
fications of forms which the same organ undurofocs in differ- 
ent animals. 

MoKPnOL'OGiY is that brancli of zoology, in its widest sense, 
which treats of the general form (not outline) and organiza- 
tion of animals, and the principles involved, as well as the 
correspondence in the various forms of tlie several members 
and parts, so far as tliey are comparable in any structural 
characters, but entirely independent of the uses of the parts 
and organs. It tlius contrasts with animal physiology, "which 
treats of tlie organization in whol;;, so far as respects adapta- 
tion to surroundings, as ^vell as the various parts and organs, 
so far as their uses and functions are concerned. To discover 
the unity of organization in divers3 forms of the animal king- 
dom, and the essential similarity in their mode of evolution, 
are the principal problems within the province of morphol- 
ogy. Theodore Gill. 

Mucous. An epithet for all bodies containing mucilage or mu- 
cus. It is also sometimes used synonymously with gummy. 

Mucus. A substance analogous to vegetable mucilage, from 
which, however, it differs by affording subcarbonate of am- 
monia on distillation. Mucus exudes through the skin, in a 
state of combination with a peculiar oily matter, and, drying, 
forms the epidermis. It constitutes, in part, the different 
epidcrnieous productions, as the hair, nails, wool, and horns 
of animals, feathers of birds, and scales of fish. It is found 
at the surface of the mucous membranes, and presents some 
difference in its composition and properties, according to the 
peculiar membrane from which it is obtained. Mucus pre- 
serves the membranes moist, and in a state best fitted for tho 
performance of their functions. 

Mu?x-DEEii. A small, hornless deer of Central Asia, inhabiting 
lofty mountain ranges. It is a timid, active creature of 
nocturnal habits, and is much hunted for its yield of musk, 
whicii is obtained from a sac beneath the abdomen, on tho 
male alone. The flesh is estesmed, though that of tho malo 



245 VOCABULAEY. 

is very rank and somewhat musky. It ranges from Siberia 
to Tonquin. Johnson's N. IT. Oyc. 

MCNTJAC, of India, Java, &c. , a small doer, but little over two 
feet high. The males have small horns ; the females are 
hornless. Their flesh is excellent. The Chinese muntjac, 
like the preceding, is often half domesticated, and is some- 
times bred in European parks. Johnsons N. U. Gyc. 

Myi/odo^si. An extinct edentate animal, allied to the megathe- 
riam. Lyell. 

Nar'whal, or Sea-Untcorn. It is most nearly related to the 
Vv'hite whale. Belonging to an order in which many of the 
members never develop teeth at all, it, of all animals, is sup- 
plied with a tooth altogether out of proportion to its size, and 
it is, moreover, developed in utter contravention of the rules 
of bi lateral symmetry, v/hich in e"^ery known case among 
vertebrates govern the production of the teeth. In both 
sexes the lower jaw is edentulous. The male, however, is 
provided, on the left side of the upper jaw, wiih a tusk from 
eight to ten feet long. It is straight, spirally gi'ooved ex- 
ternally, and hollowed within into a persistent pulp-cavity. 
On the right side the corresponding tooth generally remains 
hi'Jden, smooth, and solid, within the jaw. In addition to 
these, there are two small rudimentary molars concealed in 
the upper jaw. The narwhal, which is considered one of 
the greatest curiosities of natural history, attains to a length 
of fifteen feet. Its single spiracle or blow-hole is situated on 
the top of the liead. E. G. H. Day. 

Necro'sis. or death of a bone, corresponds to mortification of 
the soft structures, and is as distinct from caries as mortifica- 
tion is from ulceration. Necrosis is divided into four varie- 
ties, namely: 1. The scrofulous. 2. The superficial, or that 
which involves the outer lamellre, and presents itself in the 
. flat and long bones. 3. That form which destroys the in- 
i ternal part of a bone, and in which the outer shell is not af- 
fected. 4. That in wliich the whole thickness of the bono 
dies. W. Willianis, 

O. 

Odontal'gia. Toothache. 

Obontog'eny. Generation or mode of development of the teeth. 



VOCABULAEY. 247 

ODO^s^TOG'riAPHY. A description of tlie teeth. 

Odon'toid. Tooth-shaped. 

Odontot/ithos. a sort of incrustation, of a yellowish color, 
which forms at the caronse of the teeth, and is called ' tartar.' 
It consists of 79 parts of phosphate of iime, 12i of mucus, 1 
of a particular salivary matter, and 7^ of animal substance, 
soluble in clilorohydric acid. A species of infusoria, * dentlc- 
ola hominis,' has been found in it. 

Odontol'ogy. Au anatomical treatise of the teeth. 

Oral. Relating to the moutfi or to speech. 

Oral Epitite'liu:*.!. See 'Epithelium.' 

OiixiTiioiaiYN'cnus. An eflfodient (digj^inij), raonotrematoua 
mammal, with a horny beak resembling that of a duck, aud 
two merely fibrous cheek teeth on each side of both jaws, not 
fixed in any bone, hut only in the frwm ; with pentadactylous 
(iive-nngere:l) paws, webbed like the feet of a bird, and 
formed for swimmiupf, and with a spur in the hinder feet, 
emitting a poisonous liquid from a reservoir in the sole of the 
foot, supplied by a gland situated above the pelvis, and by 
the side of the spine. The animal is covered with a brown 
fur. It is found only in Nev»' Holland, and is sometimes 
called Water Mole. Bell. 

As the name of the order imports, the alimentary, urinary, 
and reproductive organs open into a common cloaca, as in 
birds ; mammary glands are present, secreting milk for the 
young, which are born blind and naked ; there are no prom- 
inent nipples, and the mammary openings are contained in 
slits in the integument ; M. Verreaus says the young, when 
they are able to swim, suck in the milk from the surface of 
the water, into which it is emitted. American Cyc. 

' Duck-Bill,' the English name of the Ornithorhynchus par- 
adoxus, found in Van Diemen's land and Australia. In its 
bill-like jaws, its spurs, its monotrematous character, its non- 
placontal deveiojiment, and its anatomy, it appears to be a 
connecting link between birds and mammals. The Duck-Bill 
is the only animal of its genus. It is about fifteen inches 
long; it climbs trees with facility, and dig.s burrows, often 
thirty feet long, in the river bank, with one opening above 
and another belovv^ water. It inhabits ponds and quiet 
streams, swimming about with its head somewhat elevated, 



218 VOCABULARY. 

often diving for its food, wliicli consists of insects and other 
small aquatic animals. JolinsorCs N. U. Gi/c. 

Of all the mammalia yet known, the Ornithorliynchus 
seems the most extraordinary in its conformation, exhibiting 
the perfect resemhlauce of the beak of a duck engrafted on 
the head of a quadruped. Dr. Shaw. 

Accurdini^ to Ernst H. Hae^kel, these animals " are he- 
coming less numerous year by year, and will soon he classed, 
with all their blood relations, among the extinct animals of 
our globe." 

Os. A bone ; also a mouth. 

Osteol'ogy. The part of anatomy which treats of bones. 

Osteo-sarco'ma. Disease of the bony tissue, which consists in 
softening of its laminae, and their transformation into a flesliy 
substance, analogous to that of cancer, accompanied with 
geaeral symptoms of cancerous alfection. The word has also 
often been used synonymously with 'spina ventosa.' 

O'v ARIES (ovum, egg). The two organs in oviparous animals 
in which tlie ova, the generative product of the female, are 
formed. They are termed by Galen ' testes muliebres,' since 
they are in women the analogues of the testes in men. The 
ovaries in adult women are situated on either side of the 
uteras, in the iliac fosste ; they are included in the two pel- 
vic duplicatures of the peritoneum, which are called the 
broad ligaments. Each ovary is also attached by a round, 
fibrous cord — the ovarian ligament — to the side of the uterus, 
and by a lesser fibrous cord to the fringed edge of the Fallo- 
pian oviduct. The ovary is an oblong, ovoid, flattened body, 
of a whitish color and uneven surface. It is {- to |^ an inch 
thick, I of an inch wide, and 1 inch to 1^- long; it weighs 
from 1 to 2 drachms. M Darwin Hudson, Jr. 

Oze'na. An affection of the pituitary membrane, which gives 
occasion to a disagreeable odor similar to a crushed bed-bug. 

P. 

Paleontot/ogy. The study of ancient beings. The science 
which treats of the evidences of organic life upon the earth 
during the different past geological periods of its history. 
These evidences consist in the remains of plants and animals 
imbedded or otherwise preserved in the rocky srata or upon 
their surfaces, and in other indications of animal existence, 



VOCABULARY. 249 

sucli as trails, footprints, burrows, and coprolitic or otlicr 
organic material found in the rocks. Pythagoras, Plaio, 
Aristotle, and othtr ancient,?, allude to the existence of ma- 
rine shells at a (lis: a'lce from the sea : it was considered con- 
clusive evidence tliat the rocks containing tliem had formerly 
been submer^-ed beneath the ocean. Ain. Cyc. 

Papil'la. Tlie end of the nipple, or an eminence similar to a 
nipple. 

Tlie minute elevations of the surface of the skin, tongue, 
&c. They serve to increase the extent of surface for vascular 
distribution, or subserve sensitive or mechanical purposes. 
Some contain one or more vascular loops ; others, nervous 
elements. Some are surmounted by dense epithelial fila- 
ments, as those which give the roughness to the tongue. 

^^'ebstcv. 

Par'asite. Parasites are plants which attach themselves to 
other plants, and animals which live in or on the bodies of 
other anini'ils, so as to subsist at their expense. The mis- 
tletoe is a parasitic plant, the louse a parasitic animal. 

Pari'etes. a name given to parts which form the inclosure or 
limits of different cavities of the body, as the parietcs of the 
cranium, chest, «Src. 

Parot'id. ('About the ear.') The largest of the salivary 
glands, seated under the ear and near the angle of the lower 
jaw. It secretes saliva. 

Pathol'ogy. The branch of medicine whose object is the 
knowledge of disease. It has been defined ' diseased physiol- 
ogy,' and * physiology of disease.' It is divided into general 
and special. The first considers diseases in common ; the 
second the particular history of each. It is subdivided into 
internal and external, or medical and surgical. 

Pelvis The part of the trunk which bounds the abdomen 
below. 

Pehiodomti'tis. Inflammation of the membrane that lines the 
socket of a tooth. 

Per'Os'teum. The periosteum is a fibrous, white, rer^isting 
medium, which surrounds the bones every where, except the 
teeth at their coronoe (crowns), and the parts of other bones 
that are covered with cartilage. The external surface is 
united, in a more or less intimate manner, to the adjoining 



250 TOCABULAllY. 

parts by areolat tissue. Its inner surface covers tlie bones, 
whose depressions it accurately follows. It is united to tiio 
bone by sinail fibrous i^rolongations, and especially by a pro- 
digious quantity of vessels, which penetrate their subslance. 
It unites the bones to the neighboring parts, and assists in 
their growth, either bj'' furnishing, at its inner surface, an 
albuminoas exudation, wiiicli becomes cartilaginous and at 
length ossifies, or by supporting the vessels which penetrate 
them to carry tlie materials of their nutrition. 

Petrous. Resembling stone ; having the hardness of stone. 

Phlegmon, Inflammation of the areolar texture, accompanied 
with redness, circumscribed swelling, increased heat and 
pain, which, at first, is tensive and lancinating and afterward 
pulsatory and heavy. It is apt to terminate in suppuration. 
It requires the antiphlogistic (opposed to inflammation) treat- 
ment until suppuration seems inevitable, when the suppura- 
tion must be encouraged as the next favorable termination 
to 'resolution.' 

PiA Mater, The pia mater is a very delicate membrane which 
overs the brain immediately, penetrates into its anfractuos- 
ities (grooves or furrows), and envelops also the cerebellum, 
the sjnnal prolongation, &c. 

PlTU'iTART. Concerned in the secretion of mucus or phlegm. 
A name given to several parts. 

Pituitary Membrane. (Schnaiderian membrane,) The mu- 
cous membrane which lines the nasal fossae, and extends 
to the different cavities communicating with the nose. It 
receives the impression of odors by means of the expansion 
of the olfactory nerves upon it, and is the seat of smell. 

Plas'ma. See 'Liquor Sanguinis.' 

Plastic. That which forms or serves to form. 

Pleistocene. A term used to denote the newest tertiary de- 
posits. Jolimon's N. XJ. Gyc. 

Pli'ocene. In geology, the tenn applied to the most modern 
of tertiary deposits, in which most of the fossil shells are of 
recent species. Lyell. 

With regard to animal life, the Pliocene continues the con- 
ditions of the Miocene, but with signs of decadence. The 
Pliocene was terminated by the cold or Glacial period, in 
which a remarkable lowering of temperature occurred over 



VOCABULARY. 251 

all the northern hemisphere, accompanied, at least in a por- 
tion of the time, by a very general and great subsidence, 
whic'i laid all the lower part of our continent under water. 
This terminated much of the life of the Pliocene, and re- 
plac3d it with boreal and arctic forms, some of them, like the 
great hairy Sibs.ian mammoth and the wooJly rhinoceros, fit 
sttcc2ssors of the gigantic Miocene fauna. J. W. Dawsoiu 

Pol'ypus. a name given to tumors which occur in mucous 
membranes especially, and which have been compared to cer- 
tain zoo[)hyte3. Polypi may Ibrm on every mucous mem- 
brane. They vary much in size, number, mode of adhesion, 
and intimate nature. Fibrous polypi are of a 'dense, compact 
t3sture and whitish color. They contain few vessels and do 
not degenerate into cancer. Tlic scirrhous or carcinomatous 
are true cancerous tumors, painful and bleeding. 

Pons Varolii. An eminence at the upper part of the medulla 
oblongata, first described by Varolius. It is formed by the 
union of the crura cerebri and crura cerebelli. 

Poste'iiior. Opposed to ' anterior,' which see. 

Pteii'ygoid. a name j^iven to two processes at the inferior 
surface of the sphenoid bone, the two laminae which form 
them having been compared to v/ings. 

Pylor'ig. That which relates to the ' pylorus.' An epithet 
given to different parts. 

Pylo'rus. a 'gate,' a 'guardian.' The lower or right orifice 
of the stomach is called 'pylorus' because it closes the en- 
trance into the intestinal canal, and is furnished with a cir- 
cular, flattened, fibro-niucous ring, Avliich causes the total 
closure of the stomach daring digestion in that organ. It is a 
fold of the inucous and muscular membranes of the stomach, 
and is the ' pyloric muscle' of soine authors. 

Q. 

Quadruma'na. (Quatuor, ' four,' and manus, ' hand.') A name 
employed by Blumenbach (in 1791) as an ordinal designation 
for the monkeys, lemurs, and related types, man ha^'ing 
been is dated as the representative of a peculiar order named 
Bimanus. The views thus expressed were for a long time 
pi-'i ):ninant ; but a closer study of the structure of the forma 
indicated by those names has convinced almost all livinjf 
naturalists that they were erroneously separated, and the two 



252 VOCABULARY. 

types are now generally combined in one order named Pri- 
mates, under whicli head man and tlio monkeys ar6 com- 
bined tog-ether in one sub-order (Anthropoidea), and con- 
trasted with the lemurs, which constitute another sub-order 
(Prosimit.e). Theodore Gill. 

\l. 

Rectum. The third and last portion of the great intestine. It 
forms the continuation of the sigmoid flexure of the colon, 
occupies the posterior part of the pelvis, and extends from 
the sacro- vertebral articulation to the coccyx (rump or crup- 
per bone), before which it opens outward by the orifice called 
the 'anus.' 

ReGt'ime. Mode of living; government, administration. 

Reg'imen. ~ The rational and methodical use of food and of 
everything essential to life, both in a state of health and dis- 
ease. It is often restricted in its meaning to ' diet.' It is 
sometimes used synonymously with hygiene (health). 

Ru'minant. a division of animals having four stomachs, the 
first so situated as to receive a large quantity of vegetable 
matter coarsely bruised by a first mastication, which passes 
into the second, where it is moistened and formed into little 
pellets ; these the animal has the power of bringing again to 
the mouth, to be rechewed, after which it is swallowed into 
the third stomach, from which it i:)asses into the fourth, 
where it is finally digested. Websfe): 

(Several v\'ell authenticated cases of human beings who 
ruminated their food are on record.) 

S, 

Sarco'ma. Any species of excrescence having a fleshy consist- 
ence^ 

Schneider lAisf Membrane. See ' Pituitary membrane.' 

Sclerot'ic, a heavy, resisting, opaque membrane, of a pearly 
white color and fibrous nature, which covers nearly the pos- 
terior four-fiuhs of the globe of the eye, and has the form of 
a sphere truncated before. 

Sella Tur'cica. (Turkish saddle.) A depression at the upper 
surface of the sphenoid bone, wliich is bounded, anteriorly 
and posteriorly, by the clinoid processes, and lodges the pitu- 
itary gland. It is so called from its resemblance to a Turkish 
saddle. 



VOCABULARY. 253 

Septum. A part intended to separate two cavities from each 
oriier, or to divide a principal cavity into several secondary 
cavities. 

Serous. Tiiin, watery. Relating to the most watery portion 

of auiiual liiiicis, or t.) meuibraues tliat secrete them. 

• SoL'iPED. An animal whose liuof is not cloven ; one of a group 

of animals with undivided hoofs; a soiid ungulate. Webster. 

The family ' Solipeda' consists of several species of horse, 

namely, the ass, the mule, and the quagga. Youatt. 

Sphenoid. Wedge-shaped. 

SPiiEXOin Bone. An azygous (single) bone, situate on the me- 
dian line, at the base of the craniimi. It articulates with all 
the bones of that cavity, supporting them and strengthening 
their union. Its form is singular, resembling a bat with its 
wings extended. 

Spina Vento'sa. See ' Osteo-sarcoma.' 

Styloid. (A style, a peg, a pin.) Shaped like a peg or pin. 

SuBMAx'iLLARY (from siih, 'under,' maxilla, 'the jaw'). That 
which is seated beneath the jaw. 

Suppuiia'tion. Formation or secretion of pus. It is a frequent 
termination of inflammation, and may occur in almost any of 
the tissues. This termination is announced by slight cliills, 
by remission of the pain, which, from being lancinating, be- 
comes heavy ; by a sense of weight in the part, and, when 
the collection of pus can be easily felt, by fluctuation. Wlu:u 
pus is thus formed in the areolar membrane, and is collected 
in one or more cavities, it constitutes an 'abscess.' If ii be 
formed from a surface exposed to tlie air, it is an ' ulcer.' and 
such ulcers we are in the habit of establishing artificially iu 
certain cases of disease. 

Supra. A common Latin prefix, signifying 'above.' 

Suture. A kind of immovable articulation, in which the bones 
unite by means of serrated e;lges, which are, as it were, dove- 
tailed into each other. The articulations of the greater part 
of the bones of the skull are of this kind. 

Sym'physis. a union of bones. The bond of such union. The 
aggregate of means used for retaining bones in .situ (natural 
situations) in the articulations. The name symphysis has, 
however, been more particularly appropriated to certain artic- 
ulations, as the ' symphysis pubis,' ' sacro-illac symphysis,' &c. 



254 TOCABULAEY. 

T. 

TeleosTS (or Teleostei). The name of that sub-class of fishes 
which embraces the great majority of living species, and so 
desig-nated (by Johannes Miiller) on accomit of the ossified 
condition of the skeleton in all the representatives of the 
group. Theodore Gill. 

Teratol'ogt. a treatise on monsters. 

TEa'TiARy. Third; of the third formation. In geology, a 
series of strata, more recent than the chalk, consisting of 
sandstones, clay beds, limestones, and frequently containing 
numerous fossils, a few of which are identical with existing 
species. It has been divided into Eocene, Miocene, and Pli- 
ocene, which see. Dana. 

Tinctu'r A Myrrhs. (Tincture of Myrrh.) Tonic, deohstruent 
(removing obstructions), antiseptic (opposed to putrefaction), 
and detergent. It is chiefly usad in gargles, and is applied 
to foul ulcers, spongy gums, &c. 

Tissue. By this term, in anatomy, is meant the various parts 
which, by their union, form the organs, and are, as it were, 
their anatomical elements. ' Histological anatomy ' is the 
anatomy of the tissues, Avhich are the seat of the investiga- 
tions of the pathological anatomist. The best division, in- 
deed, of diseases would be according to the tissues mainly 
implicated. 

Tox'ODON. A gigantic, pachydermatous quadruped, now ex- 
tinct, having teeth bent like a bow. Brande. 

Transuda'tion. (To sweat.) The passage of a fluid through 
the tissue of any organ, which may collect in small drops on 
the opposite surface, or evaporate from it. 

TREPmNE'. The instrument which has replaced the trepan in 
some countries. It consists of a simple, cylindrical saw, with 
a handle placed transversely, like that of a gimlet ; from the 
center of tlie circle described by the saw a sharp little per- 
forator, called the center-]>in, projects. The center-pin is 
capable of being removed, at the surgeon's option, by means 
of a key. It is used to fix the instrument until the teeth of 
the saw have made a groove sufficiently deep for it to work 
steadily. The pin must then he removed. Sometimes the 
pin is made to slide up and down, and to be fixed in any 
position, by means of a screw. 



VOCABULARY. 255 

Tko'car. An instrument used for evacuating fluids from cavi- 
ties, particularly in ascites (serous fluid in the abdomen, or, 
more properly, dropsy of tiie peritoneum), hydrocele (watery 
tumors), &c. A trocar consists of a perforator, or stylet, and 
a canula. The canala is so adapted to the perforator that, 
I when the puncture is made, both enter tiie wound with facil- 
ity ; the perforator, being then withdrawn, the fluid escapes 
through the canula. 

Tu'beucle. a tumor in the substance of organs, from the pro- 
duction of new matter ; sensation null, growth sluggish. In 
pathological anatomy, the term is generally given to a spe- 
cies of degeneration which consists of an opaque matter, of a 
pale yellow color. This, in its crude condition, has a con- 
sistence analogous to that of concrete albumen. It subse- 
quently becomes soft and friable, and gradually acquires a 
consistence and appearance analogous to that of bone. Tu- 
bercles may be developed in diffl-rent parts of the body, but 
they most frequently occur in the lungs and mesentery. 

Punic. An envelop. A name given to different membranes 
which envelop organs, as the tunics or coats of the eye, 
stomach, bladder, &c. 

TuRGBs'CENCE. Superabundance of humors in a part. The 
term 'turgescenc3 of bile' was formerly used to denote the 
passage of that fluid into the stomach, and its discharge by 
vomiting. 

Tympani'tes. a flatulent distention of the belly ; tympany. 
(Also inflammation of the lining membrane of the middle 
ear.) 

u. 

Un'gulate. Shai^ed like a hoof. Having hoofs, as ungulate 

quadrupeds. Webster. 

U'VEA (from uvea, a grape). The choroid coat of the eye ; the 

posterior layer of the iris. 
U'VEOUS. Resembling a grape ; applied to the choroid coat of 

the eye. 

Y. 
VAs'ctJLAR. That which belongs or relates to vessels — arterial, 

venous, lymphatic — but generally restricted to blood-vessels 

only. Full of vessels. 
Velu-M Pala'ti. The soft palate. (Uvula.) 



256 VOCABULARY. 

Veb'tebr^. The bones wLich form the spinal column. 

Tis'cus (plural, vis'cera). One of the organs contained in the 
great cavities of the body ; any one of the contents of the 
cranium, thorax, or abdomen ; in the plural, especially ap- 
l>lied to the contents of the abdomen, as the stomacli, intes- 
tines, &c. Webste7\ 

Vit'iieous. Of, pertaining to, or dorived from glass. The vit- 
reous humor of the oye is so called because it resembles 
melted glass. 

Z. 

Zool'ogy. That part of biology (science of life) which relates 
to animal life, and, as generally understood, the science 
which treats of the structure, classification, distribution, hab- 
its, and derivation of living animals. In its broadest sense, 
however, zoology includes the structure, relations, and his- 
tories of extinct as vv^ell as living forms ; but this branch of 
the science is generally considered by itself under the title 
of ' paleontology.' The derivation and life-histories of many 
groups of aniihals have been found written in the records of 
the past, and many mysteries, not only of relation but of 
structure, have been solved by going back to find dwarfed 
organs in full development and wldely-s .^pirated forms linked 
together. The zoology of the future will therefore include 
the animal life of b;3tli the past and the present. 

J. S. Neicberry. 

Zygomat'tc. That which rebates to the zygoma or cheek bone. 



INDEX. 



Alfort, Veterinary College of, 

140. 142. 
AJleu, J. T., 198. 
Amt'i'icas, the, ricliness of fossil 

remains of, 114. 
Anchippus, teeth of, 96. 
Ancliitheriam, teeth of, 96, 111, 

lie. 

Anoplothere, t(;eth of, 65. 
Antelope moutana, 08. 
Apparatus, dental, exuberance 

of particular parts of, 141-3. 
Apsyrtus, advice of, 116. 
Arcades (of teeth) anomalies in 

form of, 140, 141. 
Arisi"otle, mistake of, 63. 
Arloing, M., resection of nerves, 

2i7. 
Armadillo, the, 229. 
Astor Library, the, 4. 

Babtrgton, B., 242. 

Bac'jn, Francis, theory of, 15. 

Bdcer, S., report of, 181, 182. 

Birauni, Mr., 124. 

Batrachia, tlie, 229, 230. 

Bav, Sariyeon, discoverv of, 117. 

B.^il, C, disc weries of, 217, 218. 

Bell, a. J , 218. 

Bji!, Thom-is, theories of, 26, 

27, 83. 81. 
Bcrirer-Perrlere, discoveries of, 

116.117. j 

B.jrzelius, discoveries of, 15. 
"Bisiio,)iug," modus operandi, 

of, 211. I 



Black, Surgeon, experiment of, 
29. 

Blaine, Surgeon, fracture lower 
jaw, 197. 

Blastema, the, nature and color 
of, 34, 35. 

Boar, the masked, grinders of, 
10. 

Bojauus, discoveries of, 52. 

Bunliome, M., 127. 

Bond's Dental Medicine, extract 
from, 128, 129. 

Bouley, M. H., development of 
teeth, 45 ; grinders, 62 ; for- 
mation of enamel, 61; growth 
of teetli during life, 73; dis- 
eases of teeth, 138; diseases 
and dentistry of teeth, 139 to 
162 ; swallowing teeth, 192, 
193 ; removal of fractured 
iaw, 197, 198. 

Bourgelat, Prof, 69. 

Brace. Mr., 99. 

Bioadhoad. G. C, account of 
f-'ssil tooth, 112, 113. 

Broderip, Mr., a whale's tooth, 
79. 

Burns, John, 239. 

CAcnALOT, the, 79. 
Calcigerous, origin and use of 

Avord, 18. 
Cattle, teething period of, 91, 93. 
Camel, the, toeth of, 66. 
Camper, Pierre, ou temporary 

cauines, 52. 



358 



IKDEX. 



Canines, temporary, 51, 53. 
Calculus Concretions, 193, 193, 

Caries, cause and symptoms of, 
114 to 154 ; treatmeat oi", loO 
to 171 ; definition of, 281. 

Cartwriglit, W. A., report of, 
193 ; fracture of jawbone, 196. 

Cattauacl), C. C, 4. 

Cattanacn, J. S., 4. 

Caucasian Races, teeth of, 09. 

Cement, the, 9 ; size ot tubes of, 
1*5 ; use of, 17 ; mistaken for 
tartar, 17 ; vascularity of, 17 ; 
thinness of, 17 ; color of, 18 ; 
resemblance to bone, 23 ; 
germs of, 43 ; a protecting 
varnish, 59, 60 ; cells of, 133. 

Chauveau, A., harmony of teeth 
with general system, 11 ; de- 
velopment of tooth-germs, 41, 
42; description of incisors, 58, 
59, 00 ; growth of teeth dur- 
ing life, 73. 

Cherry, W. A., shedding teeth, 
50, 51 ; judging age by shape 
of teeth, 204. 

Chevrotaln. the, 78 ; description 
of, 232. 

CLiy w^ovth, Sujg , report of, 197. 

Coleman, Surgeon, cUscoverv of. 
116. 

Coluber Scaber, the, 121. 

Comparative Amitomy, 233. 

Conrad, T., discovery of, 113. 

Cboper Union, the, 4. 

Cope, Prof, on evolution, 238. 

Copybara, the, grinders of, 10 ; 
.descrii)tion of, 233. 

Cougliing and Teething', 02. 

Cox, Stephen J., 4. 

Cuvier, M., 16 ; note on, 66 ; 
bones and teeth of recent and 
fossil horse?, 106 ; ophthalmic 
ganglion, 221. 

Dana, Prof., geology and evo- 
lution, 240. ' 
Dandini, J. , theory of, 26. 
D'Arboval, teething, 87. 



Darwin, C. R., tushes of various 
animals, 77, 78, 79 ; changes 
in human teeth, 9;.). 

Dawson, J. W. , geology, 240 ; 
miocene period, 244 ; plio- 
cene period, 250. 

Day, E. C. 11., uarv/hal, 246. 

Delafond, M., theory of, 161. 

Denenbourg, F., report of, 123. 

Dental Cysts, 115 to 126. 

Dentinal, origin and use of 
word, 8. 

Dentinal Tubes, oiRce and color 
of, 22, 23 ; their two curva- 
tures, 23 ; the puip, 33, 34 ; 
dichotomously branched, 131, 
1;J3 ; daameter of, 132 ; length 
of curves, 133. 

Dentine, the, 8, 14. 

Dentine Germ, 43, 59. 

Dentition Fever, 93. 

Dentition, permanent, 53 to 74. 

Dentition, tem]>orary, 47 to 52. 

Dentition, third, cases of, 128. 

Dinoceras mirabilis, horns and 
canine teeth of, 236. 

Draper, John.W,, 4. 

Dugong, the, 79 ; description of, 

Duuglison, E., development of 

teeth, 45; diseases of teeth, 
137 ; vocabulary, 227 to 256. 

Edinbuegh Veterinat^y Col- 
lege, report of, 170, 180. 

Editor Veterinarian, comments 
of, 184 ; report of, 201, 202. 

Elasmothere, the, enamel fes- 
toons of molars of, 107 ; con- 
necting link between horse 
and rliinocerds, 107. 

Elephant, grinders of, 10. 

Embryology, 80 to 82. 

Enamel, the, 10; tubes of, 18, 
1-,) ; color of, 19 ; membranous 
si 1 cat] IS of, 59 ; plications of, 
106. 

Enamel- Fibers, direction of, 20 ; 
curves of, 20 ; form and size 
of, 20 ; diameter of, 134. 



INDEX. 



259 



Enterprise, the, 193. jGrouille, Mage, 116. 

Eocene (period) fossils of, 23f>. jGuanaco, the, 78 ; description 

Evolution, doctrine of, 7'7 to 79 : of, ■340. 

237, 238. Gubernaculum Dcntis, the, 43. 

Exostoses, 17, IIG. Gurlt, Sarg., discovery of, 117. 



Faenkel, discoveries of, 15. j 

Foiraeld, R G., 4. ' 

Falconer, Dr., 77. i 

Fakonio, Sur., discovery of, 118. 

Ferpjuson, P. B., development 
of teeth, 40 ; pTiuders, G2 ;' 
the formation of enamel, 64 ; 
growth of teeth during life, 
73 ; diseases of teeth, 138 ; dis- 
eases and dentistry of teeth, 
139 to 162 ; swallowing teeth, 
192, 193. 

Fetus within a Fetus, 119. 

Fleming, G., dental cysts, 115 
to 119 ; fractured jaw, 195, 
106. 

Foithomme, M., temporary ca- 
nines, 52. 

Fossil Tooth, a diseased, 173. 

Fracture! Jaws, 194 to 202. 

Frederick, M. M., 193. 

Gamgee, J , report of, 120-3. 

Garengeot, M , 156. 

General!, Prof., 116. 

Geology, definition of, 240. 

Gill, T., nature of "teeth, 12 ; 
dental formula f u' horse, 101 ; 
morphology, 245 ; quadruma- 
na, 251, 252 ; teleosts, 254. 

Girard, M., teeth and age, 206, 
207. 

Gloag, Surgeon, 182. 

Gom pilosis, 73. 

Goodsir, Prof, 125. 

Goubaux, Sur., discovery of, 117. 

Gowjng, T. W., diseases of 
teeth, 171, 173. 

Grice, C. C, report of, 123, 124. 

Grinders, the, 54 ; tables of, 61 ; 
figures formed by, 61 ; con- 
trasts between, 61. 62; their 
own whetstones, 63; roots of, 
68,70; shedding of, 70, 71. 



•Tae'^kel, E. H., embryos, 81-2. 

Harris, Prof., 3d dentition, 129. 

Hartshorne, 11., evoluti<m, 237. 

Haschischat ed dab, efiect of on 
teeth, 25. 

Hayes, B., theories of, 23 to 24; 
diseases of teeth, 137. 

Heard, J. M., 4, 216. 

Heath, J. P., report of, 200, 201. 

Eienocque, M., motor nerves, 
217, 218. 

Herbert, W. H., age, 214, 215. 

Hipparion, the, teeth of, 95, 96, 
111,112. 

Hippopotamus, the, canine teeth 
of, 63. 

Histology, definition of, 241. 

Hog, canine teeth of, 63. 

Horsburgh, J,, report of, 175. 

Horse, the, theory of introduc- 
tion into America, 110. 

Horse, the fossil, 95 to 98 ; 106 
to 113 ; extinction of in South 
America, 109. 

Houghton, S. D., 200. 

House, G. D., 4 ; size of tooth- 
germs, 31 ; theory of teeth- 
ing, 47, 48 ; grinders, 62 ; 
remnant teeih, 103, 104; re- 
moval fractured tooth through 
nostril, 198, 199; operations 
in Worcester, Mass., 199. 

Hudson, E. D., Jr., ovaries, 248. 

Hunter. J., ttie :»ries of, 24 to 27 ; 
enamel of grinders, 63 ; at- 
tachment of teeth, 72 ; use of 
canines, 83 ; su[5ernunierary 
teeth, 128; proving the for- 
mation of new dentine, 209. 

Hughes, J., dimensions of teeth, 
49; ])eriosteum of teeth, 137. 

Huxley, T. H., teeth of tapir, 
rhinoceros, and horse, (iiy, (jd; 
fossil horses, 110, 111. 



260 



liN'DEX. 



Hyoliippus, the, 113. 

Igua'todon, tlie, molars of, 63. 
Incisors, the permaneut, 5'd ; 

length of, 57 ; curvatures of, 

57; Chauveau's description of, 

5S to 60. 
Incisors, temporary, 47 to 50. 
Inferior Maxillary Nerve, the, 

228, 324. 

Knowlson, J. C, bishoping, 
211. 

Lafosse, Prof., dental cysts, 
130. 

Lanii>as, cause of, 88 to 91. 

Lanzillotti-Biionsanti, Prof., on 
dental cysts, 114. 

Lecoq, Prof., canine follicles, 44 ; 
temporary canines, 53 ; de- 
scription of grinders, 69 to 
71 ; do. canines, 77; remnant 
teeth, 100. 

Leeawenho^k, discoveries of, 13. 

Legros, C, experiments of, 37. 

Leidy, J., letter from, 101 ; fos- 
sil teeth, 113 ; mastodon, 114. 

Lincoln, A., 211. 

Lion, tiie, canine teeth of, 83. 

Liquor Sanguinis, the, 23, 342. 

Lubln, II., discovery of, 137. 

Lyell, Mr., 110. 

MvcROrs, Surgeon, experiences 
of, 117-18. 

Madder, effect of on teeth. 24. 

Magitot, E.,27; development of 
tooth-^erms, human fetus, 46. 

Malpighi, discoveries of, 13. 

Man, canine teeth of, 82, 83. 

Man, early progenitors of, 80-3. 

Marks, dimensions of, 57, 53 ; 
twofol.l use of, 301. 

Marsh, 0. C, evolution of horse. 
95 t.) 93 ; no ' mark' in teeth 
of early forms, 293; descrip- 
tion of mastodon and mega- 
therium, 313 

Mastodon, the, 100, 114, 243. 



May, C, report of, 178, 179. 

May hew, E., the cement, 17, 18 ; 
judging age by teetii, 307-8. 

Mayo, Mr., experiments of, 313. 

Meg-utberium, the, teeth of, 107, 
lo8 ; description of, 243. 

Melanian Kaces, teeth of, 99. 

Membrana Nictitans, 244. 

Mer > chippiiS, the, 113. 

Mesohippus, the, toes of, 97, 113. 

Miocene (period) fossils of, 344. 

Miohipptts, the, 113. 

Molars, the, 54 ; inclination of, 
54. 

Moon -Blindness, cause of, 105. 

Moore, T., 35, 26. 

Morphology, definition of, 345. 

Morton, Prof., 193. 

Miiller, Prof., discovery of, 14-5. 

Muntjac-Deer, the, 77, 78 ; de- 
scription of, 246. 

Musk-Deer, the, 78 ; description 
of 345 

Mylodon, the, 108, 346. 

Nakwhal, the, tushes of, 79; 

description of, 346, 
Newberry, J. S., zoology, 256. 

Niebuhr, opinion of, 25. 
Nippers, the, 47. 
NoLt, Dr., 113. 

Odontolithos, the, 17, 247. 

Odontonecrosis, 13b. 

Odontrypy, 138. 

Ohlinger, 0. P., discovery of, 
113. 

Ophthalmic Nerve, the, 219-22. 

Oruithorhynchus, the, 80 ; de- 
scription of, 347. 

Operating, rules for, 154 to 160. 

Oreste, Surg., discovery of, 118. 

Oroliipyms, the, t 'eth of, 96, 97; 
to-sof, 97; size of, 97, 112. 

Osbiston, Supt., 193. 

Osteo-sarcoma, case of, 186. 

OvvM3n, R., dental science, 8, 10, 
12, 28 ; tooth-germs, 32 to 37 
breadth and thickness, 49 
temporary canines, 51 ; teeth- 



INDEX. 



2G1 



in^, 53 ; description of grind- 1 
ers, ()4 to GO ; teetli ot aiioplo- 1 
there, Go ; do. ruminants, G5 ; ; 
do, tapir, G5 ; do. rhinoceros, j 
C7; do. megcitherium, 107 ;| 
reamant leo:ii, 102; fossil' 
hors.-'s' teeth, lOo to 109 ; 1 
: microscopical appearance of 
horses' teeth, l;jO lo 185 ; dis- 
eases of teeth, 137 ; diseased 
fossil tooth, 173, 174; the' 
fifth pair of nerves, 235, 32G. 

Paleontology, 248. 

Paleothere, teeth of, 68, 111. 

Parnell, C, remnant teeth, 102. 

Parrot-Mouth, 167, 168. 

PatholoQiy of the Teeth, 136. 

Percivail, W., teething, SQ to 
88 ; lampas, 88 to 90 ; dis- 
eases of teeth, 138, 185, 18G; 
ophthalmic aanglion, 221. 

Plasse, M., 156. 

Pliocene (period) fossils of, 250. 

Pliohippus, the, 112. 

Pony, o-reat suffering of a, 201. 

Portal, learning of, 14. 

Premolars, the, 53 ; inclination 
of, 54. 

Processes, alveolar, diseases of, 
166, 1G7. 

Protolii))pus, the, 112, 

Pulpal Cavity, relation of, 22, 

Purkinje, discoveries of, 14, 16 ; 
corpuscles of, 9 ; cells of, 16. 

QuADRi MANA, the, 36, 81, 251. 

Quain, Jonas, fifth nerve and 

ophthalmic gan<?lion, 220. 

Renault, P^of . , report of, 187. 

Kegimen, 102 to 164. 

Ketzius, Prof., discoveries and 

conjsctures of, 16, 19, 20, 21, 
Revel, M,, re])ort of, 197. 
Reversion, doctrine of, 80. 
Rhinoceros, the, teeth of, 67. 
Rhinoceros, the woolly, 251. 
RitTot, temporary canines, 52, 
Robin, C, 27. 



Rodet, Surgeon, 118, 
Roudanoosky, M,, 218. 
Rousseau, J\l., 48. 
Ruminants, teeth of, Go; four 

stomachs of, 252. 
Ruini, discoveries of, 69. 

Santy, a. H., report of. ISO. 
Scelid there, remains of, 108. 
Schaaff;:aui-en, Prof., 90. 
Schwann, Dr., researches of, 20. 
Seelye, J. H., 234. 
Sewell, W., dental cysts, 122. 
Simonds, Prof,, 156. 
Sinuses, descrii)tion of the. 152; 

gutta-percha recommended as 

a filling for, 177. 
Smith, W., report of, 182 to 184. 
Smitli, W, B., 4, 
Speculum Oris, use of, 149. 
S[}encer, H. , evolution, 237. 
Sjw, the Worcester, 199, 
Star, dentinal. -59, 209. 
Sun, the New York, 200. 
Superior Maxillary Nerve, the, 

222, 223, 
Supernumerary Teeth, 127 to 

129; 139. 
Surmon, H.. report of, 177. 
Swallowing a Diseased Tooth, 

deatli of a horse from, 187. 
Swan, Dr,, 225. 

Tables of Geixders, the, 61. 

Tapir, the, teeth ot, 65, 

Te6tli, variety and use of, 10, 
11 ; in harmony with general 
system, 11 ; readily preserved 
in a fossil state, 12 ; tubes of, 
12 ; l»ow affected by madder, 
24 to 26 ; transplanting of, 26. 

Teeth, horses', tem])orary, 47 to 
52 ; permanent. 53 to 74 ; ca- 
nines 75 to 93; remnant, 94 
to 114; abnormal, 115 to 127; 
supernumerary, 1^9; under 
the microscope, 130 to 135 ; 
]iathology of. 136 to 174 ; den- 
tistry of, 175 to 193; indica- 
tors of age, 203 to 215, 



262 



INDEX. 



Teeth, remnant, 94; reffai-ded 
as phenomenons, 94, 101 ; line 
of descent, 94 ; not to i^e con- 
founded with siipernnmeraiy 
teeth, 94 ; why named rem- 
nant, 94; easily lost, 90, 100. 

Tenon, discovery of, Gc). 

Thurber, (1., 4. 

Tomes, C. S., tooth-g-emis, 37 to 
41; temporary canines, 52; 
dentine, enamel, and cement, 
63 ; attachment of teeth, 72 ; 
gTowtli of (iiorses') teerh dur- 
ing life, 74 ; tuslies of boars, 
84, 85 ; evolution, 98, 99 ; no 
' mark ' in teeth of early fossil 
horses. 203. 

Tomes, J., a tooth barricading 
disease, 189. 

Tooth, nature of, 7, 8; irides- 
cence of, 12, 16 ; no inherent 
power of reparation, 137. 

Tootli and Bone, analogy of. 23. 

Tooth-Germs, development of, 
31 to 46. 

Tooth-Cough, 92. 

Tooth, a diseased fossil, 173-4. 

Tooth Pulp, description of the, 
31. 

Toxodon, remains of, 109 ; de- 
scription of, 254. 

Trephine, the, 254. 

Irephining Sinuses, 157 to 161. 

Tripier, M., resection of nerves, 
217. 

Trocar, the, 255. 

Tushes, horses', [jractically use- 
less, 75 ; different from other 
teeth, 75; distances from in- 
cisors and grinders, 75, 76 ; 
shape and dimensions of, 76 ; 
curvatures of roots, 70. 

Tushes, removal of, 155. 

Varnell, G., opinion of, 102; 
diseasesof teeth, 1C8, 139; the 
sinuses, 151, 153, 161 ; Ci^ries, 
164 to 166 ; diseases of alveo- 



lar processes, 160, 167 ; par- 
rot-mouth, 107, 168 ; osteo- 
sarcoma, 186, 187; fractured 
jaws, 194. 

Vv^'allace, a. R., cause of de- 
struction of ungulata. 111 ; 
fossil horses, 112 ; geology, 
210. 

Walrus, the, mode of fighting 
of, 77. 

Walsh, J H., judging age by 
teeth, 208. 

Williams, Prof. W., teething, 
91; remnant teeth, 104, 105; 
dental cvsts, 125 to 127 ; ca- 
ries, 169'to 171. 

Williams, W., necrosis, 246. 

Winter, J. H., use of tushes, 85. 

V/oodward, J. J., histology, 241. 

Works, general, 4. 

Works, special, 4, 

Wyman, Prof., discovery of, 81. 

YouATT, W., sugar ns food, 29 ; 
tooth-germs, 44, 45; infundi- 
bula of grinders, 58 ; move- 
ment of lower jaw, 62 ; use 
of tushes, 84 ; teething, 85-6 ; 
lampas, 90; croppinp; iiorses' 
ears, 103 ; remnant teeth, 105 ; 
food, 162 to 164 ; diseases of 
teeth, 172, 173; fractured 
jaws, 196 to 198; 'mark' of 
central nippers, 205 ; difficul- 
ties of judging age, 207 ; bish- 
oping, 211 ; trade tricks, 212, 
214 ; crib-biting, 212, 213 ; in- 
dications of age independent 
of teeth, 214; fifth i air of 
nerves, 216 to 225 ; csecum, 
230: colon, 232; membrana 
nictitans, 244 ; solipeds. 253. 

Youmans, E. L.. evolution, 237. 

Zebra, temporary canine teeth 

of, 52. 
Zoology, definition of, 256. 



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